diff --git a/Userland/Libraries/LibWeb/DOM/Document.cpp b/Userland/Libraries/LibWeb/DOM/Document.cpp
index 5c146b5f673..9b498fd04c3 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Document.cpp
@@ -2974,7 +2974,7 @@ void Document::destroy()
 
     // 7. Set document's node navigable's active session history entry's document state's document to null.
     if (navigable()) {
-        navigable()->active_session_history_entry()->document_state->set_document(nullptr);
+        navigable()->active_session_history_entry()->document_state()->set_document(nullptr);
     }
 
     // FIXME: 8. Remove document from the owner set of each WorkerGlobalScope object whose set contains document.
@@ -3790,7 +3790,7 @@ void Document::restore_the_history_object_state(JS::NonnullGCPtr<HTML::SessionHi
 
     // 2. Let state be StructuredDeserialize(entry's classic history API state, targetRealm). If this throws an exception, catch it and let state be null.
     // 3. Set document's history object's state to state.
-    auto state_or_error = HTML::structured_deserialize(target_realm.vm(), entry->classic_history_api_state, target_realm, {});
+    auto state_or_error = HTML::structured_deserialize(target_realm.vm(), entry->classic_history_api_state(), target_realm, {});
     if (state_or_error.is_error())
         m_history->set_state(JS::js_null());
     else
@@ -3818,7 +3818,7 @@ void Document::update_for_history_step_application(JS::NonnullGCPtr<HTML::Sessio
     //      The doNotReactivate argument distinguishes between these two cases.
     if (documents_entry_changed) {
         // 1. Let oldURL be document's latest entry's URL.
-        auto old_url = m_latest_entry ? m_latest_entry->url : URL::URL {};
+        auto old_url = m_latest_entry ? m_latest_entry->url() : URL::URL {};
 
         // 2. Set document's latest entry to entry.
         m_latest_entry = entry;
diff --git a/Userland/Libraries/LibWeb/Dump.cpp b/Userland/Libraries/LibWeb/Dump.cpp
index 8378b9ea77b..29e02858ac3 100644
--- a/Userland/Libraries/LibWeb/Dump.cpp
+++ b/Userland/Libraries/LibWeb/Dump.cpp
@@ -53,9 +53,9 @@ static void indent(StringBuilder& builder, int levels)
 static ErrorOr<void> dump_session_history_entry(StringBuilder& builder, HTML::SessionHistoryEntry const& session_history_entry, int indent_levels)
 {
     indent(builder, indent_levels);
-    auto const& document = session_history_entry.document_state->document();
-    TRY(builder.try_appendff("step=({}) url=({}) is-active=({})\n", session_history_entry.step.get<int>(), session_history_entry.url, document && document->is_active()));
-    for (auto const& nested_history : session_history_entry.document_state->nested_histories()) {
+    auto const& document = session_history_entry.document_state()->document();
+    TRY(builder.try_appendff("step=({}) url=({}) is-active=({})\n", session_history_entry.step().get<int>(), session_history_entry.url(), document && document->is_active()));
+    for (auto const& nested_history : session_history_entry.document_state()->nested_histories()) {
         for (auto const& nested_she : nested_history.entries) {
             TRY(dump_session_history_entry(builder, *nested_she, indent_levels + 1));
         }
diff --git a/Userland/Libraries/LibWeb/Forward.h b/Userland/Libraries/LibWeb/Forward.h
index 0406287bd16..949ce7733ad 100644
--- a/Userland/Libraries/LibWeb/Forward.h
+++ b/Userland/Libraries/LibWeb/Forward.h
@@ -483,7 +483,7 @@ struct POSTResource;
 struct ScrollOptions;
 struct ScrollToOptions;
 struct SerializedFormData;
-struct SessionHistoryEntry;
+class SessionHistoryEntry;
 struct ToggleTaskTracker;
 }
 
diff --git a/Userland/Libraries/LibWeb/HTML/Navigable.cpp b/Userland/Libraries/LibWeb/HTML/Navigable.cpp
index 8aff3c46695..c5bf31480b2 100644
--- a/Userland/Libraries/LibWeb/HTML/Navigable.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Navigable.cpp
@@ -77,7 +77,7 @@ Vector<JS::Handle<Navigable>> Navigable::child_navigables() const
 {
     Vector<JS::Handle<Navigable>> results;
     for (auto& entry : all_navigables()) {
-        if (entry->current_session_history_entry()->step == SessionHistoryEntry::Pending::Tag)
+        if (entry->current_session_history_entry()->step() == SessionHistoryEntry::Pending::Tag)
             continue;
         if (entry->parent() == this)
             results.append(entry);
@@ -140,10 +140,10 @@ ErrorOr<void> Navigable::initialize_navigable(JS::NonnullGCPtr<DocumentState> do
     JS::NonnullGCPtr<SessionHistoryEntry> entry = *heap().allocate_without_realm<SessionHistoryEntry>();
 
     // URL: document's URL
-    entry->url = document_state->document()->url();
+    entry->set_url(document_state->document()->url());
 
     // document state: documentState
-    entry->document_state = document_state;
+    entry->set_document_state(document_state);
 
     // 2. Set navigable's current session history entry to entry.
     m_current_session_history_entry = entry;
@@ -166,9 +166,9 @@ JS::GCPtr<SessionHistoryEntry> Navigable::get_the_target_history_entry(int targe
     // 2. Return the item in entries that has the greatest step less than or equal to step.
     JS::GCPtr<SessionHistoryEntry> result = nullptr;
     for (auto& entry : entries) {
-        auto entry_step = entry->step.get<int>();
+        auto entry_step = entry->step().get<int>();
         if (entry_step <= target_step) {
-            if (!result || result->step.get<int>() < entry_step) {
+            if (!result || result->step().get<int>() < entry_step) {
                 result = entry;
             }
         }
@@ -183,7 +183,7 @@ void Navigable::activate_history_entry(JS::GCPtr<SessionHistoryEntry> entry)
     // FIXME: 1. Save persisted state to the navigable's active session history entry.
 
     // 2. Let newDocument be entry's document.
-    JS::GCPtr<DOM::Document> new_document = entry->document_state->document().ptr();
+    JS::GCPtr<DOM::Document> new_document = entry->document_state()->document().ptr();
 
     // 3. Assert: newDocument's is initial about:blank is false, i.e., we never traverse
     //    back to the initial about:blank Document because it always gets replaced when we
@@ -205,7 +205,7 @@ void Navigable::activate_history_entry(JS::GCPtr<SessionHistoryEntry> entry)
 JS::GCPtr<DOM::Document> Navigable::active_document()
 {
     // A navigable's active document is its active session history entry's document.
-    return m_active_session_history_entry->document_state->document();
+    return m_active_session_history_entry->document_state()->document();
 }
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#nav-bc
@@ -240,7 +240,7 @@ JS::GCPtr<HTML::Window> Navigable::active_window()
 String Navigable::target_name() const
 {
     // A navigable's target name is its active session history entry's document state's navigable target name.
-    return active_session_history_entry()->document_state->navigable_target_name();
+    return active_session_history_entry()->document_state()->navigable_target_name();
 }
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#nav-container
@@ -478,7 +478,7 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>>& Navigable::get_session_history_en
 
     // 5. For each entry of traversable's session history entries, append entry's document state to docStates.
     for (auto& entry : traversable->session_history_entries())
-        doc_states.append(entry->document_state);
+        doc_states.append(entry->document_state());
 
     // 6. For each docState of docStates:
     while (!doc_states.is_empty()) {
@@ -492,7 +492,7 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>>& Navigable::get_session_history_en
 
             // 2. For each entry of nestedHistory's entries, append entry's document state to docStates.
             for (auto& entry : nested_history.entries)
-                doc_states.append(entry->document_state);
+                doc_states.append(entry->document_state());
         }
     }
 
@@ -585,7 +585,7 @@ static WebIDL::ExceptionOr<NavigationParams> create_navigation_params_from_a_src
     auto& realm = navigable->active_window()->realm();
 
     // 1. Let documentResource be entry's document state's resource.
-    auto document_resource = entry->document_state->resource();
+    auto document_resource = entry->document_state()->resource();
     VERIFY(document_resource.has<String>());
 
     // 2. Let response be a new response with
@@ -599,7 +599,7 @@ static WebIDL::ExceptionOr<NavigationParams> create_navigation_params_from_a_src
     response->set_body(TRY(Fetch::Infrastructure::byte_sequence_as_body(realm, document_resource.get<String>().bytes())));
 
     // 3. Let responseOrigin be the result of determining the origin given response's URL, targetSnapshotParams's sandboxing flags, and entry's document state's origin.
-    auto response_origin = determine_the_origin(*response->url(), target_snapshot_params.sandboxing_flags, entry->document_state->origin());
+    auto response_origin = determine_the_origin(*response->url(), target_snapshot_params.sandboxing_flags, entry->document_state()->origin());
 
     // 4. Let coop be a new cross-origin opener policy.
     CrossOriginOpenerPolicy coop = {};
@@ -616,7 +616,7 @@ static WebIDL::ExceptionOr<NavigationParams> create_navigation_params_from_a_src
 
     // 6. Let policyContainer be the result of determining navigation params policy container given response's URL,
     //    entry's document state's history policy container, null, navigable's container document's policy container, and null.
-    Optional<PolicyContainer> history_policy_container = entry->document_state->history_policy_container().visit(
+    Optional<PolicyContainer> history_policy_container = entry->document_state()->history_policy_container().visit(
         [](PolicyContainer const& c) -> Optional<PolicyContainer> { return c; },
         [](DocumentState::Client) -> Optional<PolicyContainer> { return {}; });
     PolicyContainer policy_container;
@@ -655,7 +655,7 @@ static WebIDL::ExceptionOr<NavigationParams> create_navigation_params_from_a_src
         .policy_container = policy_container,
         .final_sandboxing_flag_set = target_snapshot_params.sandboxing_flags,
         .cross_origin_opener_policy = move(coop),
-        .about_base_url = entry->document_state->about_base_url(),
+        .about_base_url = entry->document_state()->about_base_url(),
     };
 }
 
@@ -671,7 +671,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
     // FIXME: 1. Assert: this is running in parallel.
 
     // 2. Let documentResource be entry's document state's resource.
-    auto document_resource = entry->document_state->resource();
+    auto document_resource = entry->document_state()->resource();
 
     // 3. Let request be a new request, with
     //    url: entry's URL
@@ -685,7 +685,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
     //    referrer: entry's document state's request referrer
     //    referrer policy: entry's document state's request referrer policy
     auto request = Fetch::Infrastructure::Request::create(vm);
-    request->set_url(entry->url);
+    request->set_url(entry->url());
     request->set_client(source_snapshot_params.fetch_client);
     request->set_destination(Fetch::Infrastructure::Request::Destination::Document);
     request->set_credentials_mode(Fetch::Infrastructure::Request::CredentialsMode::Include);
@@ -693,7 +693,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
     request->set_redirect_mode(Fetch::Infrastructure::Request::RedirectMode::Manual);
     request->set_replaces_client_id(active_document.relevant_settings_object().id);
     request->set_mode(Fetch::Infrastructure::Request::Mode::Navigate);
-    request->set_referrer(entry->document_state->request_referrer());
+    request->set_referrer(entry->document_state()->request_referrer());
 
     // 4. If documentResource is a POST resource, then:
     if (document_resource.has<POSTResource>()) {
@@ -722,11 +722,11 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
     }
 
     // 5. If entry's document state's reload pending is true, then set request's reload-navigation flag.
-    if (entry->document_state->reload_pending())
+    if (entry->document_state()->reload_pending())
         request->set_reload_navigation(true);
 
     // 6. Otherwise, if entry's document state's ever populated is true, then set request's history-navigation flag.
-    if (entry->document_state->ever_populated())
+    if (entry->document_state()->ever_populated())
         request->set_history_navigation(true);
 
     // 7. If sourceSnapshotParams's has transient activation is true, then set request's user-activation to true.
@@ -777,7 +777,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
         .url = active_document.url(),
         .origin = active_document.origin(),
         .cross_origin_opener_policy = active_document.cross_origin_opener_policy(),
-        .current_context_is_navigation_source = entry->document_state->initiator_origin().has_value() && active_document.origin().is_same_origin(*entry->document_state->initiator_origin())
+        .current_context_is_navigation_source = entry->document_state()->initiator_origin().has_value() && active_document.origin().is_same_origin(*entry->document_state()->initiator_origin())
     };
 
     // 13. Let finalSandboxFlags be an empty sandboxing flag set.
@@ -856,14 +856,14 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
 
         // 8. If request's body is null, then set entry's document state's resource to null.
         if (!request->body().has<Empty>()) {
-            entry->document_state->set_resource(Empty {});
+            entry->document_state()->set_resource(Empty {});
         }
 
         // FIXME 9. Set responsePolicyContainer to the result of creating a policy container from a fetch response given response and request's reserved client.
         // FIXME 10. Set finalSandboxFlags to the union of targetSnapshotParams's sandboxing flags and responsePolicyContainer's CSP list's CSP-derived sandboxing flags.
 
         // 11. Set responseOrigin to the result of determining the origin given response's URL, finalSandboxFlags, and entry's document state's initiator origin.
-        response_origin = determine_the_origin(*response_holder->response()->url(), final_sandbox_flags, entry->document_state->initiator_origin());
+        response_origin = determine_the_origin(*response_holder->response()->url(), final_sandbox_flags, entry->document_state()->initiator_origin());
 
         // 12. If navigable is a top-level traversable, then:
         if (navigable->is_top_level_traversable()) {
@@ -898,10 +898,10 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
         VERIFY(location_url.value()->is_valid());
 
         // 17. Set entry's classic history API state to StructuredSerializeForStorage(null).
-        entry->classic_history_api_state = MUST(structured_serialize_for_storage(vm, JS::js_null()));
+        entry->set_classic_history_api_state(MUST(structured_serialize_for_storage(vm, JS::js_null())));
 
         // 18. Let oldDocState be entry's document state.
-        auto old_doc_state = entry->document_state;
+        auto old_doc_state = entry->document_state();
 
         // 19. Set entry's document state to a new document state, with
         // history policy container: a clone of the oldDocState's history policy container if it is non-null; null otherwise
@@ -911,19 +911,20 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
         // resource: oldDocState's resource
         // ever populated: oldDocState's ever populated
         // navigable target name: oldDocState's navigable target name
-        entry->document_state = navigable->heap().allocate_without_realm<DocumentState>();
-        entry->document_state->set_history_policy_container(old_doc_state->history_policy_container());
-        entry->document_state->set_request_referrer(old_doc_state->request_referrer());
-        entry->document_state->set_request_referrer_policy(old_doc_state->request_referrer_policy());
-        entry->document_state->set_origin(old_doc_state->origin());
-        entry->document_state->set_resource(old_doc_state->resource());
-        entry->document_state->set_ever_populated(old_doc_state->ever_populated());
-        entry->document_state->set_navigable_target_name(old_doc_state->navigable_target_name());
+        auto new_document_state = navigable->heap().allocate_without_realm<DocumentState>();
+        new_document_state->set_history_policy_container(old_doc_state->history_policy_container());
+        new_document_state->set_request_referrer(old_doc_state->request_referrer());
+        new_document_state->set_request_referrer_policy(old_doc_state->request_referrer_policy());
+        new_document_state->set_origin(old_doc_state->origin());
+        new_document_state->set_resource(old_doc_state->resource());
+        new_document_state->set_ever_populated(old_doc_state->ever_populated());
+        new_document_state->set_navigable_target_name(old_doc_state->navigable_target_name());
+        entry->set_document_state(new_document_state);
 
         // 20. If locationURL's scheme is not an HTTP(S) scheme, then:
         if (!Fetch::Infrastructure::is_http_or_https_scheme(location_url.value()->scheme())) {
             // 1. Set entry's document state's resource to null.
-            entry->document_state->set_resource(Empty {});
+            entry->document_state()->set_resource(Empty {});
 
             // 2. Break.
             break;
@@ -933,7 +934,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
         current_url = location_url.value().value();
 
         // 22. Set entry's URL to currentURL.
-        entry->url = current_url;
+        entry->set_url(current_url);
     }
 
     // 20. If locationURL is a URL whose scheme is not a fetch scheme, then return a new non-fetch scheme navigation params, with
@@ -970,7 +971,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
 
     // 23. Let resultPolicyContainer be the result of determining navigation params policy container given response's URL,
     //     entry's document state's history policy container, sourceSnapshotParams's source policy container, null, and responsePolicyContainer.
-    Optional<PolicyContainer> history_policy_container = entry->document_state->history_policy_container().visit(
+    Optional<PolicyContainer> history_policy_container = entry->document_state()->history_policy_container().visit(
         [](PolicyContainer const& c) -> Optional<PolicyContainer> { return c; },
         [](DocumentState::Client) -> Optional<PolicyContainer> { return {}; });
     auto result_policy_container = determine_navigation_params_policy_container(*response_holder->response()->url(), history_policy_container, source_snapshot_params.source_policy_container, {}, response_policy_container);
@@ -1007,7 +1008,7 @@ static WebIDL::ExceptionOr<Variant<Empty, NavigationParams, NonFetchSchemeNaviga
         .policy_container = result_policy_container,
         .final_sandboxing_flag_set = final_sandbox_flags,
         .cross_origin_opener_policy = response_coop,
-        .about_base_url = entry->document_state->about_base_url(),
+        .about_base_url = entry->document_state()->about_base_url(),
     };
 
     return navigation_params;
@@ -1035,7 +1036,7 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
     [[maybe_unused]] auto current_browsing_context = active_browsing_context();
 
     // 4. Let documentResource be entry's document state's resource.
-    auto document_resource = entry->document_state->resource();
+    auto document_resource = entry->document_state()->resource();
 
     // 5. If navigationParams is null, then:
     if (navigation_params.has<Empty>()) {
@@ -1048,11 +1049,11 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
         // 2. Otherwise, if both of the following are true:
         //    - entry's URL's scheme is a fetch scheme; and
         //    - documentResource is null, or allowPOST is true and documentResource's request body is not failure (FIXME: check if request body is not failure)
-        else if (Fetch::Infrastructure::is_fetch_scheme(entry->url.scheme()) && (document_resource.has<Empty>() || allow_POST)) {
+        else if (Fetch::Infrastructure::is_fetch_scheme(entry->url().scheme()) && (document_resource.has<Empty>() || allow_POST)) {
             navigation_params = TRY(create_navigation_params_by_fetching(entry, this, source_snapshot_params, target_snapshot_params, csp_navigation_type, navigation_id));
         }
         // 3. Otherwise, if entry's URL's scheme is not a fetch scheme, then set navigationParams to a new non-fetch scheme navigation params, with:
-        else if (!Fetch::Infrastructure::is_fetch_scheme(entry->url.scheme())) {
+        else if (!Fetch::Infrastructure::is_fetch_scheme(entry->url().scheme())) {
             // - id: navigationId
             // - navigable: navigable
             // - URL: entry's URL
@@ -1063,10 +1064,10 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
             navigation_params = NonFetchSchemeNavigationParams {
                 .id = navigation_id,
                 .navigable = this,
-                .url = entry->url,
+                .url = entry->url(),
                 .target_snapshot_sandboxing_flags = target_snapshot_params.sandboxing_flags,
                 .source_snapshot_has_transient_activation = source_snapshot_params.has_transient_activation,
-                .initiator_origin = *entry->document_state->initiator_origin(),
+                .initiator_origin = *entry->document_state()->initiator_origin(),
             };
         }
     }
@@ -1095,9 +1096,9 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
         if (navigation_params.has<NonFetchSchemeNavigationParams>()) {
             // FIXME: https://github.com/whatwg/html/issues/9767
             // We probably are expected to skip to steps 13 and 14 and return after doing this
-            entry->document_state->set_document(attempt_to_create_a_non_fetch_scheme_document(navigation_params.get<NonFetchSchemeNavigationParams>()));
-            if (entry->document_state->document()) {
-                entry->document_state->set_ever_populated(true);
+            entry->document_state()->set_document(attempt_to_create_a_non_fetch_scheme_document(navigation_params.get<NonFetchSchemeNavigationParams>()));
+            if (entry->document_state()->document()) {
+                entry->document_state()->set_ever_populated(true);
             }
             completion_steps();
             return;
@@ -1122,15 +1123,15 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
             // 1. Set entry's document state's document to the result of creating a document for inline content that doesn't have a DOM, given navigable, null, and navTimingType.
             //    The inline content should indicate to the user the sort of error that occurred.
             // FIXME: Add error message to generated error page
-            auto error_html = load_error_page(entry->url).release_value_but_fixme_should_propagate_errors();
-            entry->document_state->set_document(create_document_for_inline_content(this, navigation_id, [error_html](auto& document) {
+            auto error_html = load_error_page(entry->url()).release_value_but_fixme_should_propagate_errors();
+            entry->document_state()->set_document(create_document_for_inline_content(this, navigation_id, [error_html](auto& document) {
                 auto parser = HTML::HTMLParser::create(document, error_html, "utf-8");
                 document.set_url(URL::URL("about:error"));
                 parser->run();
             }));
 
             // 2. Set entry's document state's document's salvageable to false.
-            entry->document_state->document()->set_salvageable(false);
+            entry->document_state()->document()->set_salvageable(false);
 
             // FIXME: 3. If navigationParams is not null, then:
             if (!navigation_params.has<Empty>()) {
@@ -1162,10 +1163,10 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
             }
 
             // 3. Set entry's document state's document to document.
-            entry->document_state->set_document(document.ptr());
+            entry->document_state()->set_document(document.ptr());
 
             // 4. Set entry's document state's origin to document's origin.
-            entry->document_state->set_origin(document->origin());
+            entry->document_state()->set_origin(document->origin());
         }
 
         // FIXME: 12. If entry's document state's request referrer is "client", then set it to request's referrer.
@@ -1173,8 +1174,8 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
         //     What is "request" here?
 
         // 13. If entry's document state's document is not null, then set entry's document state's ever populated to true.
-        if (entry->document_state->document()) {
-            entry->document_state->set_ever_populated(true);
+        if (entry->document_state()->document()) {
+            entry->document_state()->set_ever_populated(true);
         }
 
         // 14. Run completionSteps.
@@ -1273,7 +1274,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate(NavigateParams params)
     //    - url's fragment is non-null
     if (document_resource.has<Empty>()
         && !response
-        && url.equals(active_session_history_entry()->url, URL::ExcludeFragment::Yes)
+        && url.equals(active_session_history_entry()->url(), URL::ExcludeFragment::Yes)
         && url.fragment().has_value()) {
         // 1. Navigate to a fragment given navigable, url, historyHandling, userInvolvement, navigationAPIState, and navigationId.
         TRY(navigate_to_a_fragment(url, to_history_handling_behavior(history_handling), user_involvement, navigation_api_state, navigation_id));
@@ -1402,8 +1403,8 @@ WebIDL::ExceptionOr<void> Navigable::navigate(NavigateParams params)
 
         // 6. Let historyEntry be a new session history entry, with its URL set to url and its document state set to documentState.
         JS::NonnullGCPtr<SessionHistoryEntry> history_entry = *heap().allocate_without_realm<SessionHistoryEntry>();
-        history_entry->url = url;
-        history_entry->document_state = document_state;
+        history_entry->set_url(url);
+        history_entry->set_document_state(document_state);
 
         // 7. Let navigationParams be null.
         Variant<Empty, NavigationParams, NonFetchSchemeNavigationParams> navigation_params = Empty {};
@@ -1445,7 +1446,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate_to_a_fragment(URL::URL const& url,
 
     // 2. Let destinationNavigationAPIState be navigable's active session history entry's navigation API state.
     // 3. If navigationAPIState is not null, then set destinationNavigationAPIState to navigationAPIState.
-    auto destination_navigation_api_state = navigation_api_state.has_value() ? *navigation_api_state : active_session_history_entry()->navigation_api_state;
+    auto destination_navigation_api_state = navigation_api_state.has_value() ? *navigation_api_state : active_session_history_entry()->navigation_api_state();
 
     // 4. Let continue be the result of firing a push/replace/reload navigate event at navigation with navigationType set to historyHandling, isSameDocument set to true,
     //    userInvolvement set to userInvolvement, and destinationURL set to url, and navigationAPIState set to destinationNavigationAPIState.
@@ -1462,10 +1463,10 @@ WebIDL::ExceptionOr<void> Navigable::navigate_to_a_fragment(URL::URL const& url,
     //      navigation API state: destinationNavigationAPIState
     //      scroll restoration mode: navigable's active session history entry's scroll restoration mode
     JS::NonnullGCPtr<SessionHistoryEntry> history_entry = heap().allocate_without_realm<SessionHistoryEntry>();
-    history_entry->url = url;
-    history_entry->document_state = active_session_history_entry()->document_state;
-    history_entry->navigation_api_state = destination_navigation_api_state;
-    history_entry->scroll_restoration_mode = active_session_history_entry()->scroll_restoration_mode;
+    history_entry->set_url(url);
+    history_entry->set_document_state(active_session_history_entry()->document_state());
+    history_entry->set_navigation_api_state(destination_navigation_api_state);
+    history_entry->set_scroll_restoration_mode(active_session_history_entry()->scroll_restoration_mode());
 
     // 7. Let entryToReplace be navigable's active session history entry if historyHandling is "replace", otherwise null.
     auto entry_to_replace = history_handling == HistoryHandlingBehavior::Replace ? active_session_history_entry() : nullptr;
@@ -1658,7 +1659,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate_to_a_javascript_url(URL::URL const
     auto entry_to_replace = active_session_history_entry();
 
     // 10. Let oldDocState be entryToReplace's document state.
-    auto old_doc_state = entry_to_replace->document_state;
+    auto old_doc_state = entry_to_replace->document_state();
 
     // 11. Let documentState be a new document state with
     //     document: newDocument
@@ -1686,8 +1687,8 @@ WebIDL::ExceptionOr<void> Navigable::navigate_to_a_javascript_url(URL::URL const
     //     URL: entryToReplace's URL
     //     document state: documentState
     JS::NonnullGCPtr<SessionHistoryEntry> history_entry = *heap().allocate_without_realm<SessionHistoryEntry>();
-    history_entry->url = entry_to_replace->url;
-    history_entry->document_state = document_state;
+    history_entry->set_url(entry_to_replace->url());
+    history_entry->set_document_state(document_state);
 
     // 13. Append session history traversal steps to targetNavigable's traversable to finalize a cross-document navigation with targetNavigable, historyHandling, and historyEntry.
     traversable_navigable()->append_session_history_traversal_steps([this, history_entry, history_handling, navigation_id] {
@@ -1701,7 +1702,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate_to_a_javascript_url(URL::URL const
 void Navigable::reload()
 {
     // 1. Set navigable's active session history entry's document state's reload pending to true.
-    active_session_history_entry()->document_state->set_reload_pending(true);
+    active_session_history_entry()->document_state()->set_reload_pending(true);
 
     // 2. Let traversable be navigable's traversable navigable.
     auto traversable = traversable_navigable();
@@ -1804,7 +1805,7 @@ void finalize_a_cross_document_navigation(JS::NonnullGCPtr<Navigable> navigable,
     navigable->set_delaying_load_events(false);
 
     // 3. If historyEntry's document is null, then return.
-    if (!history_entry->document_state->document())
+    if (!history_entry->document_state()->document())
         return;
 
     // 4. If all of the following are true:
@@ -1812,8 +1813,8 @@ void finalize_a_cross_document_navigation(JS::NonnullGCPtr<Navigable> navigable,
     //    - historyEntry's document's browsing context is not an auxiliary browsing context whose opener browsing context is non-null; and
     //    - historyEntry's document's origin is not navigable's active document's origin
     //    then set historyEntry's document state's navigable target name to the empty string.
-    if (navigable->parent() == nullptr && history_entry->document_state->document()->browsing_context()->opener_browsing_context() != nullptr && history_entry->document_state->document()->origin() != navigable->active_document()->origin())
-        history_entry->document_state->set_navigable_target_name(String {});
+    if (navigable->parent() == nullptr && history_entry->document_state()->document()->browsing_context()->opener_browsing_context() != nullptr && history_entry->document_state()->document()->origin() != navigable->active_document()->origin())
+        history_entry->document_state()->set_navigable_target_name(String {});
 
     // 5. Let entryToReplace be navigable's active session history entry if historyHandling is "replace", otherwise null.
     auto entry_to_replace = history_handling == HistoryHandlingBehavior::Replace ? navigable->active_session_history_entry() : nullptr;
@@ -1836,7 +1837,7 @@ void finalize_a_cross_document_navigation(JS::NonnullGCPtr<Navigable> navigable,
         target_step = traversable->current_session_history_step() + 1;
 
         // 3. Set historyEntry's step to targetStep.
-        history_entry->step = target_step;
+        history_entry->set_step(target_step);
 
         // 4. Append historyEntry to targetEntries.
         target_entries.append(history_entry);
@@ -1845,12 +1846,12 @@ void finalize_a_cross_document_navigation(JS::NonnullGCPtr<Navigable> navigable,
         *(target_entries.find(*entry_to_replace)) = history_entry;
 
         // 2. Set historyEntry's step to entryToReplace's step.
-        history_entry->step = entry_to_replace->step;
+        history_entry->set_step(entry_to_replace->step());
 
         // 3. If historyEntry's document state's origin is same origin with entryToReplace's document state's origin,
         //    then set historyEntry's navigation API key to entryToReplace's navigation API key.
-        if (history_entry->document_state->origin().has_value() && entry_to_replace->document_state->origin().has_value() && history_entry->document_state->origin()->is_same_origin(*entry_to_replace->document_state->origin())) {
-            history_entry->navigation_api_key = entry_to_replace->navigation_api_key;
+        if (history_entry->document_state()->origin().has_value() && entry_to_replace->document_state()->origin().has_value() && history_entry->document_state()->origin()->is_same_origin(*entry_to_replace->document_state()->origin())) {
+            history_entry->set_navigation_api_key(entry_to_replace->navigation_api_key());
         }
 
         // 4. Set targetStep to traversable's current session history step.
@@ -1878,10 +1879,10 @@ void perform_url_and_history_update_steps(DOM::Document& document, URL::URL new_
     //      scroll restoration mode: activeEntry's scroll restoration mode
     // FIXME: persisted user state: activeEntry's persisted user state
     JS::NonnullGCPtr<SessionHistoryEntry> new_entry = document.heap().allocate_without_realm<SessionHistoryEntry>();
-    new_entry->url = new_url;
-    new_entry->classic_history_api_state = serialized_data.value_or(active_entry->classic_history_api_state);
-    new_entry->document_state = active_entry->document_state;
-    new_entry->scroll_restoration_mode = active_entry->scroll_restoration_mode;
+    new_entry->set_url(new_url);
+    new_entry->set_classic_history_api_state(serialized_data.value_or(active_entry->classic_history_api_state()));
+    new_entry->set_document_state(active_entry->document_state());
+    new_entry->set_scroll_restoration_mode(active_entry->scroll_restoration_mode());
 
     // 4. If document's is initial about:blank is true, then set historyHandling to "replace".
     if (document.is_initial_about_blank()) {
diff --git a/Userland/Libraries/LibWeb/HTML/NavigableContainer.cpp b/Userland/Libraries/LibWeb/HTML/NavigableContainer.cpp
index 32f040ee2d9..df645856d02 100644
--- a/Userland/Libraries/LibWeb/HTML/NavigableContainer.cpp
+++ b/Userland/Libraries/LibWeb/HTML/NavigableContainer.cpp
@@ -112,18 +112,18 @@ WebIDL::ExceptionOr<void> NavigableContainer::create_new_child_navigable()
     traversable->append_session_history_traversal_steps([traversable, navigable, parent_navigable, history_entry] {
         // 1. Let parentDocState be parentNavigable's active session history entry's document state.
 
-        auto parent_doc_state = parent_navigable->active_session_history_entry()->document_state;
+        auto parent_doc_state = parent_navigable->active_session_history_entry()->document_state();
 
         // 2. Let parentNavigableEntries be the result of getting session history entries for parentNavigable.
         auto parent_navigable_entries = parent_navigable->get_session_history_entries();
 
         // 3. Let targetStepSHE be the first session history entry in parentNavigableEntries whose document state equals parentDocState.
         auto target_step_she = *parent_navigable_entries.find_if([parent_doc_state](auto& entry) {
-            return entry->document_state == parent_doc_state;
+            return entry->document_state() == parent_doc_state;
         });
 
         // 4. Set historyEntry's step to targetStepSHE's step.
-        history_entry->step = target_step_she->step;
+        history_entry->set_step(target_step_she->step());
 
         // 5. Let nestedHistory be a new nested history whose id is navigable's id and entries list is « historyEntry ».
         DocumentState::NestedHistory nested_history {
@@ -267,7 +267,7 @@ void NavigableContainer::destroy_the_child_navigable()
     navigable->active_document()->destroy();
 
     // 6. Let parentDocState be container's node navigable's active session history entry's document state.
-    auto parent_doc_state = this->navigable()->active_session_history_entry()->document_state;
+    auto parent_doc_state = this->navigable()->active_session_history_entry()->document_state();
 
     // 7. Remove the nested history from parentDocState's nested histories whose id equals navigable's id.
     parent_doc_state->nested_histories().remove_all_matching([&](auto& nested_history) {
diff --git a/Userland/Libraries/LibWeb/HTML/Navigation.cpp b/Userland/Libraries/LibWeb/HTML/Navigation.cpp
index b9e9f43534c..75817aafda3 100644
--- a/Userland/Libraries/LibWeb/HTML/Navigation.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Navigation.cpp
@@ -140,7 +140,7 @@ WebIDL::ExceptionOr<void> Navigation::update_current_entry(NavigationUpdateCurre
     auto serialized_state = TRY(structured_serialize_for_storage(vm(), options.state));
 
     // 4. Set current's session history entry's navigation API state to serializedState.
-    current->session_history_entry().navigation_api_state = serialized_state;
+    current->session_history_entry().set_navigation_api_state(serialized_state);
 
     // 5. Fire an event named currententrychange at this using NavigationCurrentEntryChangeEvent,
     //    with its navigationType attribute initialized to null and its from initialized to current.
@@ -310,7 +310,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::reload(NavigationReloadOptions
 
         // 2. If current is not null, then set serializedState to current's session history entry's navigation API state.
         if (current != nullptr)
-            serialized_state = current->session_history_entry().navigation_api_state;
+            serialized_state = current->session_history_entry().navigation_api_state();
     }
 
     // 5. If document is not fully active, then return an early error result for an "InvalidStateError" DOMException.
@@ -347,7 +347,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::traverse_to(String key, Naviga
     // 2. If this's entry list does not contain a NavigationHistoryEntry whose session history entry's navigation API key equals key,
     //    then return an early error result for an "InvalidStateError" DOMException.
     auto it = m_entry_list.find_if([&key](auto const& entry) {
-        return entry->session_history_entry().navigation_api_key == key;
+        return entry->session_history_entry().navigation_api_key() == key;
     });
     if (it == m_entry_list.end())
         return early_error_result(WebIDL::InvalidStateError::create(realm, "Cannot traverseTo: key not found in session history list"_fly_string));
@@ -367,7 +367,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::back(NavigationOptions const&
         return early_error_result(WebIDL::InvalidStateError::create(realm, "Cannot navigate back: no previous session history entry"_fly_string));
 
     // 2. Let key be this's entry list[this's current entry index − 1]'s session history entry's navigation API key.
-    auto key = m_entry_list[m_current_entry_index - 1]->session_history_entry().navigation_api_key;
+    auto key = m_entry_list[m_current_entry_index - 1]->session_history_entry().navigation_api_key();
 
     // 3. Return the result of performing a navigation API traversal given this, key, and options.
     return perform_a_navigation_api_traversal(key, options);
@@ -385,7 +385,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::forward(NavigationOptions cons
         return early_error_result(WebIDL::InvalidStateError::create(realm, "Cannot navigate forward: no next session history entry"_fly_string));
 
     // 2. Let key be this's entry list[this's current entry index + 1]'s session history entry's navigation API key.
-    auto key = m_entry_list[m_current_entry_index + 1]->session_history_entry().navigation_api_key;
+    auto key = m_entry_list[m_current_entry_index + 1]->session_history_entry().navigation_api_key();
 
     // 3. Return the result of performing a navigation API traversal given this, key, and options.
     return perform_a_navigation_api_traversal(key, options);
@@ -622,7 +622,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::perform_a_navigation_api_trave
 
     // 5. If key equals current's session history entry's navigation API key, then return
     //    «[ "committed" → a promise resolved with current, "finished" → a promise resolved with current ]».
-    if (key == current->session_history_entry().navigation_api_key) {
+    if (key == current->session_history_entry().navigation_api_key()) {
         return NavigationResult {
             .committed = WebIDL::create_resolved_promise(realm, current)->promise(),
             .finished = WebIDL::create_resolved_promise(realm, current)->promise()
@@ -656,7 +656,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::perform_a_navigation_api_trave
 
         // 2. Let targetSHE be the session history entry in navigableSHEs whose navigation API key is key. If no such entry exists, then:
         auto it = navigable_shes.find_if([&key](auto const& entry) {
-            return entry->navigation_api_key == key;
+            return entry->navigation_api_key() == key;
         });
         if (it == navigable_shes.end()) {
             // NOTE: This path is taken if navigation's entry list was outdated compared to navigableSHEs,
@@ -684,7 +684,7 @@ WebIDL::ExceptionOr<NavigationResult> Navigation::perform_a_navigation_api_trave
 
         // 4. Let result be the result of applying the traverse history step given by targetSHE's step to traversable,
         //    given sourceSnapshotParams, navigable, and "none".
-        auto result = traversable->apply_the_traverse_history_step(target_she->step.get<int>(), source_snapshot_params, navigable, UserNavigationInvolvement::None);
+        auto result = traversable->apply_the_traverse_history_step(target_she->step().get<int>(), source_snapshot_params, navigable, UserNavigationInvolvement::None);
 
         // NOTE: When result is "canceled-by-beforeunload" or "initiator-disallowed", the navigate event was never fired,
         //       aborting the ongoing navigation would not be correct; it would result in a navigateerror event without a
@@ -885,7 +885,7 @@ void Navigation::notify_about_the_committed_to_entry(JS::NonnullGCPtr<Navigation
     if (api_method_tracker->serialized_state.has_value()) {
         // NOTE: At this point, apiMethodTracker's serialized state is no longer needed.
         //       Implementations might want to clear it out to avoid keeping it alive for the lifetime of the navigation API method tracker.
-        nhe->session_history_entry().navigation_api_state = *api_method_tracker->serialized_state;
+        nhe->session_history_entry().set_navigation_api_state(*api_method_tracker->serialized_state);
         api_method_tracker->serialized_state = {};
     }
 
@@ -1244,7 +1244,7 @@ bool Navigation::fire_a_traverse_navigate_event(JS::NonnullGCPtr<SessionHistoryE
     auto destination = NavigationDestination::create(realm);
 
     // 4. Set destination's URL to destinationSHE's URL.
-    destination->set_url(destination_she->url);
+    destination->set_url(destination_she->url());
 
     // 5. Let destinationNHE be the NavigationHistoryEntry in navigation's entry list whose session history entry is destinationSHE,
     //    or null if no such NavigationHistoryEntry exists.
@@ -1258,7 +1258,7 @@ bool Navigation::fire_a_traverse_navigate_event(JS::NonnullGCPtr<SessionHistoryE
         destination->set_entry(*destination_nhe);
 
         // 2. Set destination's state to destinationSHE's navigation API state.
-        destination->set_state(destination_she->navigation_api_state);
+        destination->set_state(destination_she->navigation_api_state());
     }
 
     // 7. Otherwise:
@@ -1272,7 +1272,7 @@ bool Navigation::fire_a_traverse_navigate_event(JS::NonnullGCPtr<SessionHistoryE
 
     // 8. Set destination's is same document to true if destinationSHE's document is equal to
     //    navigation's relevant global object's associated Document; otherwise false.
-    destination->set_is_same_document(destination_she->document_state->document() == &verify_cast<Window>(relevant_global_object(*this)).associated_document());
+    destination->set_is_same_document(destination_she->document_state()->document() == &verify_cast<Window>(relevant_global_object(*this)).associated_document());
 
     // 9. Return the result of performing the inner navigate event firing algorithm given navigation, "traverse", event, destination, userInvolvement, null, and null.
     // AD-HOC: We don't pass the event, but we do pass the classic_history_api state at the end to be set later
diff --git a/Userland/Libraries/LibWeb/HTML/NavigationHistoryEntry.cpp b/Userland/Libraries/LibWeb/HTML/NavigationHistoryEntry.cpp
index 3a1d541e15d..653dd17c41d 100644
--- a/Userland/Libraries/LibWeb/HTML/NavigationHistoryEntry.cpp
+++ b/Userland/Libraries/LibWeb/HTML/NavigationHistoryEntry.cpp
@@ -59,13 +59,13 @@ WebIDL::ExceptionOr<Optional<String>> NavigationHistoryEntry::url() const
 
     // 4. If she's document does not equal document, and she's document state's request referrer policy
     //    is "no-referrer" or "origin", then return null.
-    if ((she->document_state->document() != &document)
-        && (she->document_state->request_referrer_policy() == ReferrerPolicy::ReferrerPolicy::NoReferrer
-            || she->document_state->request_referrer_policy() == ReferrerPolicy::ReferrerPolicy::Origin))
+    if ((she->document_state()->document() != &document)
+        && (she->document_state()->request_referrer_policy() == ReferrerPolicy::ReferrerPolicy::NoReferrer
+            || she->document_state()->request_referrer_policy() == ReferrerPolicy::ReferrerPolicy::Origin))
         return OptionalNone {};
 
     // 5. Return she's URL, serialized.
-    return TRY_OR_THROW_OOM(vm(), String::from_byte_string(she->url.serialize()));
+    return TRY_OR_THROW_OOM(vm(), String::from_byte_string(she->url().serialize()));
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#concept-navigationhistoryentry-key
@@ -78,7 +78,7 @@ String NavigationHistoryEntry::key() const
         return {};
 
     // 2. Return nhe's session history entry's navigation API key.
-    return m_session_history_entry->navigation_api_key;
+    return m_session_history_entry->navigation_api_key();
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#concept-navigationhistoryentry-id
@@ -91,7 +91,7 @@ String NavigationHistoryEntry::id() const
         return {};
 
     // 2. Return nhe's session history entry's navigation API ID.
-    return m_session_history_entry->navigation_api_id;
+    return m_session_history_entry->navigation_api_id();
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#concept-navigationhistoryentry-index
@@ -120,7 +120,7 @@ bool NavigationHistoryEntry::same_document() const
         return false;
 
     // 3. Return true if this's session history entry's document equals document, and false otherwise.
-    return m_session_history_entry->document_state->document() == &document;
+    return m_session_history_entry->document_state()->document() == &document;
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#dom-navigationhistoryentry-getstate
@@ -135,7 +135,7 @@ WebIDL::ExceptionOr<JS::Value> NavigationHistoryEntry::get_state()
     // 2. Return StructuredDeserialize(this's session history entry's navigation API state). Rethrow any exceptions.
     //    NOTE: This can in theory throw an exception, if attempting to deserialize a large ArrayBuffer
     //          when not enough memory is available.
-    return structured_deserialize(vm(), m_session_history_entry->navigation_api_state, realm(), {});
+    return structured_deserialize(vm(), m_session_history_entry->navigation_api_state(), realm(), {});
 }
 
 void NavigationHistoryEntry::set_ondispose(WebIDL::CallbackType* event_handler)
diff --git a/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.cpp b/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.cpp
index eafaa5c9b61..6df31acec4d 100644
--- a/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.cpp
+++ b/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.cpp
@@ -16,15 +16,15 @@ JS_DEFINE_ALLOCATOR(SessionHistoryEntry);
 void SessionHistoryEntry::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
-    visitor.visit(document_state);
-    visitor.visit(original_source_browsing_context);
+    visitor.visit(m_document_state);
+    visitor.visit(m_original_source_browsing_context);
 }
 
 SessionHistoryEntry::SessionHistoryEntry()
-    : classic_history_api_state(MUST(structured_serialize_for_storage(vm(), JS::js_null())))
-    , navigation_api_state(MUST(structured_serialize_for_storage(vm(), JS::js_undefined())))
-    , navigation_api_key(MUST(Crypto::generate_random_uuid()))
-    , navigation_api_id(MUST(Crypto::generate_random_uuid()))
+    : m_classic_history_api_state(MUST(structured_serialize_for_storage(vm(), JS::js_null())))
+    , m_navigation_api_state(MUST(structured_serialize_for_storage(vm(), JS::js_undefined())))
+    , m_navigation_api_key(MUST(Crypto::generate_random_uuid()))
+    , m_navigation_api_id(MUST(Crypto::generate_random_uuid()))
 {
 }
 
diff --git a/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.h b/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.h
index ab8796e1a4c..eee322e5afc 100644
--- a/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.h
+++ b/Userland/Libraries/LibWeb/HTML/SessionHistoryEntry.h
@@ -28,10 +28,11 @@ enum class ScrollRestorationMode {
 };
 
 // https://html.spec.whatwg.org/multipage/history.html#session-history-entry
-struct SessionHistoryEntry final : public JS::Cell {
+class SessionHistoryEntry final : public JS::Cell {
     JS_CELL(SessionHistoryEntry, JS::Cell);
     JS_DECLARE_ALLOCATOR(SessionHistoryEntry);
 
+public:
     SessionHistoryEntry();
 
     void visit_edges(Cell::Visitor&) override;
@@ -40,51 +41,85 @@ struct SessionHistoryEntry final : public JS::Cell {
         Tag,
     };
 
+    [[nodiscard]] Variant<int, Pending> step() const { return m_step; }
+    void set_step(Variant<int, Pending> step) { m_step = step; }
+
+    [[nodiscard]] URL::URL const& url() const { return m_url; }
+    void set_url(URL::URL url) { m_url = move(url); }
+
+    [[nodiscard]] JS::GCPtr<HTML::DocumentState> document_state() const { return m_document_state; }
+    void set_document_state(JS::GCPtr<HTML::DocumentState> document_state) { m_document_state = document_state; }
+
+    [[nodiscard]] SerializationRecord const& classic_history_api_state() const { return m_classic_history_api_state; }
+    void set_classic_history_api_state(SerializationRecord classic_history_api_state) { m_classic_history_api_state = move(classic_history_api_state); }
+
+    [[nodiscard]] SerializationRecord const& navigation_api_state() const { return m_navigation_api_state; }
+    void set_navigation_api_state(SerializationRecord navigation_api_state) { m_navigation_api_state = move(navigation_api_state); }
+
+    [[nodiscard]] String const& navigation_api_key() const { return m_navigation_api_key; }
+    void set_navigation_api_key(String navigation_api_key) { m_navigation_api_key = move(navigation_api_key); }
+
+    [[nodiscard]] String const& navigation_api_id() const { return m_navigation_api_id; }
+    void set_navigation_api_id(String navigation_api_id) { m_navigation_api_id = move(navigation_api_id); }
+
+    [[nodiscard]] ScrollRestorationMode scroll_restoration_mode() const { return m_scroll_restoration_mode; }
+    void set_scroll_restoration_mode(ScrollRestorationMode scroll_restoration_mode) { m_scroll_restoration_mode = scroll_restoration_mode; }
+
+    [[nodiscard]] Optional<PolicyContainer> const& policy_container() const { return m_policy_container; }
+    void set_policy_container(Optional<PolicyContainer> policy_container) { m_policy_container = move(policy_container); }
+
+    [[nodiscard]] Optional<ByteString> const& browsing_context_name() const { return m_browsing_context_name; }
+    void set_browsing_context_name(Optional<ByteString> browsing_context_name) { m_browsing_context_name = move(browsing_context_name); }
+
+    [[nodiscard]] JS::GCPtr<BrowsingContext> original_source_browsing_context() const { return m_original_source_browsing_context; }
+    void set_original_source_browsing_context(JS::GCPtr<BrowsingContext> original_source_browsing_context) { m_original_source_browsing_context = original_source_browsing_context; }
+
+private:
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-step
     // step, a non-negative integer or "pending", initially "pending".
-    Variant<int, Pending> step { Pending::Tag };
+    Variant<int, Pending> m_step { Pending::Tag };
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-url
     // URL, a URL
-    URL::URL url;
+    URL::URL m_url;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-document-state
-    JS::GCPtr<HTML::DocumentState> document_state;
+    JS::GCPtr<HTML::DocumentState> m_document_state;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-classic-history-api-state
     // classic history API state, which is serialized state, initially StructuredSerializeForStorage(null).
-    SerializationRecord classic_history_api_state;
+    SerializationRecord m_classic_history_api_state;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-navigation-api-state
     // navigation API state, which is a serialized state, initially StructuredSerializeForStorage(undefined).
-    SerializationRecord navigation_api_state;
+    SerializationRecord m_navigation_api_state;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-navigation-api-key
     // navigation API key, which is a string, initially set to the result of generating a random UUID.
-    String navigation_api_key;
+    String m_navigation_api_key;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-navigation-api-id
     // navigation API ID, which is a string, initially set to the result of generating a random UUID.
-    String navigation_api_id;
+    String m_navigation_api_id;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-scroll-restoration-mode
     // scroll restoration mode, a scroll restoration mode, initially "auto"
-    ScrollRestorationMode scroll_restoration_mode { ScrollRestorationMode::Auto };
+    ScrollRestorationMode m_scroll_restoration_mode { ScrollRestorationMode::Auto };
 
     // policy container, a policy container or null
-    Optional<PolicyContainer> policy_container;
+    Optional<PolicyContainer> m_policy_container;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-scroll-position
     // FIXME: scroll position data, which is scroll position data for the document's restorable scrollable regions
 
     // browsing context name, a browsing context name or null, initially null
-    Optional<ByteString> browsing_context_name;
+    Optional<ByteString> m_browsing_context_name;
 
     // https://html.spec.whatwg.org/multipage/browsing-the-web.html#she-other
     // FIXME: persisted user state, which is implementation-defined, initially null
     // NOTE: This is where we could remember the state of form controls, for example.
 
-    JS::GCPtr<BrowsingContext> original_source_browsing_context;
+    JS::GCPtr<BrowsingContext> m_original_source_browsing_context;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
index dbc3e750538..78e326e7821 100644
--- a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
+++ b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
@@ -100,7 +100,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<TraversableNavigable>> TraversableNavigable
     VERIFY(initial_history_entry);
 
     // 8. Set initialHistoryEntry's step to 0.
-    initial_history_entry->step = 0;
+    initial_history_entry->set_step(0);
 
     // 9. Append initialHistoryEntry to traversable's session history entries.
     traversable->m_session_history_entries.append(*initial_history_entry);
@@ -171,10 +171,10 @@ Vector<int> TraversableNavigable::get_all_used_history_steps() const
         // 1. For each entry of entryList:
         for (auto& entry : entry_list) {
             // 1. Append entry's step to steps.
-            steps.set(entry->step.get<int>());
+            steps.set(entry->step().get<int>());
 
             // 2. For each nestedHistory of entry's document state's nested histories, append nestedHistory's entries list to entryLists.
-            for (auto& nested_history : entry->document_state->nested_histories())
+            for (auto& nested_history : entry->document_state()->nested_histories())
                 entry_lists.append(nested_history.entries);
         }
     }
@@ -244,12 +244,12 @@ Vector<JS::Handle<Navigable>> TraversableNavigable::get_all_navigables_whose_cur
         auto target_entry = navigable->get_the_target_history_entry(target_step);
 
         // 2. If targetEntry is not navigable's current session history entry or targetEntry's document state's reload pending is true, then append navigable to results.
-        if (target_entry != navigable->current_session_history_entry() || target_entry->document_state->reload_pending()) {
+        if (target_entry != navigable->current_session_history_entry() || target_entry->document_state()->reload_pending()) {
             results.append(*navigable);
         }
 
         // 3. If targetEntry's document is navigable's document, and targetEntry's document state's reload pending is false, then extend navigablesToCheck with the child navigables of navigable.
-        if (target_entry->document_state->document() == navigable->active_document() && !target_entry->document_state->reload_pending()) {
+        if (target_entry->document_state()->document() == navigable->active_document() && !target_entry->document_state()->reload_pending()) {
             navigables_to_check.extend(navigable->child_navigables());
         }
     }
@@ -279,7 +279,7 @@ Vector<JS::Handle<Navigable>> TraversableNavigable::get_all_navigables_that_only
         auto target_entry = navigable->get_the_target_history_entry(target_step);
 
         // 2. If targetEntry is navigable's current session history entry and targetEntry's document state's reload pending is false, then:
-        if (target_entry == navigable->current_session_history_entry() && !target_entry->document_state->reload_pending()) {
+        if (target_entry == navigable->current_session_history_entry() && !target_entry->document_state()->reload_pending()) {
             // 1.  Append navigable to results.
             results.append(navigable);
 
@@ -318,7 +318,7 @@ Vector<JS::Handle<Navigable>> TraversableNavigable::get_all_navigables_that_migh
         // 2. If targetEntry's document is not navigable's document or targetEntry's document state's reload pending is true, then append navigable to results.
         // NOTE: Although navigable's active history entry can change synchronously, the new entry will always have the same Document,
         //       so accessing navigable's document is reliable.
-        if (target_entry->document_state->document() != navigable->active_document() || target_entry->document_state->reload_pending()) {
+        if (target_entry->document_state()->document() != navigable->active_document() || target_entry->document_state()->reload_pending()) {
             results.append(navigable);
         }
 
@@ -421,14 +421,14 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
 
             // 3. Let changingNavigableContinuation be a changing navigable continuation state with:
             auto changing_navigable_continuation = ChangingNavigableContinuationState {
-                .displayed_document = displayed_entry->document_state->document(),
+                .displayed_document = displayed_entry->document_state()->document(),
                 .target_entry = target_entry,
                 .navigable = navigable,
                 .update_only = false
             };
 
             // 4. If displayedEntry is targetEntry and targetEntry's document state's reload pending is false, then:
-            if (displayed_entry == target_entry && !target_entry->document_state->reload_pending()) {
+            if (displayed_entry == target_entry && !target_entry->document_state()->reload_pending()) {
                 // 1. Set changingNavigableContinuation's update-only to true.
                 changing_navigable_continuation.update_only = true;
 
@@ -440,18 +440,18 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
             }
 
             // 5. Let oldOrigin be targetEntry's document state's origin.
-            auto old_origin = target_entry->document_state->origin();
+            auto old_origin = target_entry->document_state()->origin();
 
             auto after_document_populated = [old_origin, target_entry, changing_navigable_continuation, &changing_navigable_continuations, &vm, &navigable]() mutable {
                 // 1. If targetEntry's document is null, then set changingNavigableContinuation's update-only to true.
-                if (!target_entry->document_state->document()) {
+                if (!target_entry->document_state()->document()) {
                     changing_navigable_continuation.update_only = true;
                 }
 
                 else {
                     // 2. If targetEntry's document's origin is not oldOrigin, then set targetEntry's classic history API state to StructuredSerializeForStorage(null).
-                    if (target_entry->document_state->document()->origin() != old_origin) {
-                        target_entry->classic_history_api_state = MUST(structured_serialize_for_storage(vm, JS::js_null()));
+                    if (target_entry->document_state()->document()->origin() != old_origin) {
+                        target_entry->set_classic_history_api_state(MUST(structured_serialize_for_storage(vm, JS::js_null())));
                     }
 
                     // 3. If all of the following are true:
@@ -460,9 +460,9 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
                     //     - targetEntry's document's origin is not oldOrigin,
                     //    then set targetEntry's document state's navigable target name to the empty string.
                     if (navigable->parent() != nullptr
-                        && target_entry->document_state->document()->browsing_context()->opener_browsing_context() == nullptr
-                        && target_entry->document_state->origin() != old_origin) {
-                        target_entry->document_state->set_navigable_target_name(String {});
+                        && target_entry->document_state()->document()->browsing_context()->opener_browsing_context() == nullptr
+                        && target_entry->document_state()->origin() != old_origin) {
+                        target_entry->document_state()->set_navigable_target_name(String {});
                     }
                 }
 
@@ -471,7 +471,7 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
             };
 
             // 6. If targetEntry's document is null, or targetEntry's document state's reload pending is true, then:
-            if (!target_entry->document_state->document() || target_entry->document_state->reload_pending()) {
+            if (!target_entry->document_state()->document() || target_entry->document_state()->reload_pending()) {
                 // FIXME: 1. Let navTimingType be "back_forward" if targetEntry's document is null; otherwise "reload".
 
                 // 2. Let targetSnapshotParams be the result of snapshotting target snapshot params given navigable.
@@ -486,10 +486,10 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
                 }
 
                 // 5. Set targetEntry's document state's reload pending to false.
-                target_entry->document_state->set_reload_pending(false);
+                target_entry->document_state()->set_reload_pending(false);
 
                 // 6. Let allowPOST be targetEntry's document state's reload pending.
-                auto allow_POST = target_entry->document_state->reload_pending();
+                auto allow_POST = target_entry->document_state()->reload_pending();
 
                 // 7. In parallel, attempt to populate the history entry's document for targetEntry, given navigable, potentiallyTargetSpecificSourceSnapshotParams,
                 //    targetSnapshotParams, with allowPOST set to allowPOST and completionSteps set to queue a global task on the navigation and traversal task source given
@@ -593,9 +593,9 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
             // 1. If changingNavigableContinuation's update-only is false, then:
             if (!update_only) {
                 // 1. If targetEntry's document does not equal displayedDocument, then:
-                if (target_entry->document_state->document().ptr() != displayed_document.ptr()) {
+                if (target_entry->document_state()->document().ptr() != displayed_document.ptr()) {
                     // 1. Unload displayedDocument given targetEntry's document.
-                    displayed_document->unload(target_entry->document_state->document());
+                    displayed_document->unload(target_entry->document_state()->document());
 
                     // 2. For each childNavigable of displayedDocument's descendant navigables, queue a global task on the navigation and traversal task source given
                     //    childNavigable's active window to unload childNavigable's active document.
@@ -612,8 +612,8 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
 
             // 2. If navigable is not traversable, and targetEntry is not navigable's current session history entry, and targetEntry's document state's origin is the same as
             //    navigable's current session history entry's document state's origin, then fire a traverse navigate event given targetEntry and userInvolvementForNavigateEvents.
-            auto target_origin = target_entry->document_state->origin();
-            auto current_origin = navigable->current_session_history_entry()->document_state->origin();
+            auto target_origin = target_entry->document_state()->origin();
+            auto current_origin = navigable->current_session_history_entry()->document_state()->origin();
             bool const is_same_origin = target_origin.has_value() && current_origin.has_value() && target_origin->is_same_origin(*current_origin);
             if (!navigable->is_traversable()
                 && target_entry.ptr() != navigable->current_session_history_entry()
@@ -624,16 +624,16 @@ TraversableNavigable::HistoryStepResult TraversableNavigable::apply_the_history_
             // 3. Let updateDocument be an algorithm step which performs update document for history step application given targetEntry's document,
             //    targetEntry, changingNavigableContinuation's update-only, scriptHistoryLength, scriptHistoryIndex, and entriesForNavigationAPI.
             auto update_document = JS::SafeFunction<void()>([target_entry, update_only, script_history_length, script_history_index, entries_for_navigation_api = move(entries_for_navigation_api)] {
-                target_entry->document_state->document()->update_for_history_step_application(*target_entry, update_only, script_history_length, script_history_index, entries_for_navigation_api);
+                target_entry->document_state()->document()->update_for_history_step_application(*target_entry, update_only, script_history_length, script_history_index, entries_for_navigation_api);
             });
 
             // 4. If targetEntry's document is equal to displayedDocument, then perform updateDocument.
-            if (target_entry->document_state->document() == displayed_document.ptr()) {
+            if (target_entry->document_state()->document() == displayed_document.ptr()) {
                 update_document();
             }
             // 5. Otherwise, queue a global task on the navigation and traversal task source given targetEntry's document's relevant global object to perform updateDocument
             else {
-                queue_global_task(Task::Source::NavigationAndTraversal, relevant_global_object(*target_entry->document_state->document()), move(update_document));
+                queue_global_task(Task::Source::NavigationAndTraversal, relevant_global_object(*target_entry->document_state()->document()), move(update_document));
             }
 
             // 6. Increment completedChangeJobs.
@@ -707,8 +707,8 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>> TraversableNavigable::get_session_
     auto max_step = 0;
     for (auto i = 0u; i < raw_entries.size(); ++i) {
         auto const& entry = raw_entries[i];
-        if (entry->step.has<int>()) {
-            auto step = entry->step.get<int>();
+        if (entry->step().has<int>()) {
+            auto step = entry->step().get<int>();
             if (step <= target_step && step > max_step) {
                 starting_index = static_cast<int>(i);
             }
@@ -719,7 +719,7 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>> TraversableNavigable::get_session_
     entries_for_navigation_api.append(raw_entries[starting_index]);
 
     // 5. Let startingOrigin be rawEntries[startingIndex]'s document state's origin.
-    auto starting_origin = raw_entries[starting_index]->document_state->origin();
+    auto starting_origin = raw_entries[starting_index]->document_state()->origin();
 
     // 6. Let i be startingIndex − 1.
     auto i = starting_index - 1;
@@ -728,7 +728,7 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>> TraversableNavigable::get_session_
     while (i > 0) {
         auto& entry = raw_entries[static_cast<unsigned>(i)];
         // 1. If rawEntries[i]'s document state's origin is not same origin with startingOrigin, then break.
-        auto entry_origin = entry->document_state->origin();
+        auto entry_origin = entry->document_state()->origin();
         if (starting_origin.has_value() && entry_origin.has_value() && !entry_origin->is_same_origin(*starting_origin))
             break;
 
@@ -746,7 +746,7 @@ Vector<JS::NonnullGCPtr<SessionHistoryEntry>> TraversableNavigable::get_session_
     while (i < static_cast<int>(raw_entries.size())) {
         auto& entry = raw_entries[static_cast<unsigned>(i)];
         // 1. If rawEntries[i]'s document state's origin is not same origin with startingOrigin, then break.
-        auto entry_origin = entry->document_state->origin();
+        auto entry_origin = entry->document_state()->origin();
         if (starting_origin.has_value() && entry_origin.has_value() && !entry_origin->is_same_origin(*starting_origin))
             break;
 
@@ -779,13 +779,13 @@ void TraversableNavigable::clear_the_forward_session_history()
 
         // 1. Remove every session history entry from entryList that has a step greater than step.
         entry_list.remove_all_matching([step](auto& entry) {
-            return entry->step.template get<int>() > step;
+            return entry->step().template get<int>() > step;
         });
 
         // 2. For each entry of entryList:
         for (auto& entry : entry_list) {
             // 1. For each nestedHistory of entry's document state's nested histories, append nestedHistory's entries list to entryLists.
-            for (auto& nested_history : entry->document_state->nested_histories()) {
+            for (auto& nested_history : entry->document_state()->nested_histories()) {
                 entry_lists.append(nested_history.entries);
             }
         }
@@ -898,7 +898,7 @@ void TraversableNavigable::destroy_top_level_traversable()
     // 2. For each historyEntry in traversable's session history entries:
     for (auto& history_entry : m_session_history_entries) {
         // 1. Let document be historyEntry's document.
-        auto document = history_entry->document_state->document();
+        auto document = history_entry->document_state()->document();
 
         // 2. If document is not null, then destroy document.
         if (document)
@@ -953,7 +953,7 @@ void finalize_a_same_document_navigation(JS::NonnullGCPtr<TraversableNavigable>
         target_step = traversable->current_session_history_step() + 1;
 
         // 3. Set targetEntry's step to targetStep.
-        target_entry->step = *target_step;
+        target_entry->set_step(*target_step);
 
         // 4. Append targetEntry to targetEntries.
         target_entries.append(target_entry);
@@ -962,7 +962,7 @@ void finalize_a_same_document_navigation(JS::NonnullGCPtr<TraversableNavigable>
         *(target_entries.find(*entry_to_replace)) = target_entry;
 
         // 2. Set targetEntry's step to entryToReplace's step.
-        target_entry->step = entry_to_replace->step;
+        target_entry->set_step(entry_to_replace->step());
 
         // 3. Set targetStep to traversable's current session history step.
         target_step = traversable->current_session_history_step();
diff --git a/Userland/Libraries/LibWeb/HTML/Window.cpp b/Userland/Libraries/LibWeb/HTML/Window.cpp
index a6a5638069a..63708b28ea4 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Window.cpp
@@ -866,7 +866,7 @@ void Window::set_name(String const& name)
         return;
 
     // 2. Set this's navigable's active session history entry's document state's navigable target name to the given value.
-    navigable()->active_session_history_entry()->document_state->set_navigable_target_name(name);
+    navigable()->active_session_history_entry()->document_state()->set_navigable_target_name(name);
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#dom-window-status
diff --git a/Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.cpp b/Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.cpp
index 95cb61d34d8..e21ccd5926b 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.cpp
@@ -86,7 +86,7 @@ ErrorOr<JS::NonnullGCPtr<SVGDecodedImageData>> SVGDecodedImageData::create(JS::R
     auto document = DOM::Document::create_and_initialize(DOM::Document::Type::HTML, "text/html"_string, navigation_params).release_value_but_fixme_should_propagate_errors();
     navigable->set_ongoing_navigation({});
     navigable->active_document()->destroy();
-    navigable->active_session_history_entry()->document_state->set_document(document);
+    navigable->active_session_history_entry()->document_state()->set_document(document);
 
     auto parser = HTML::HTMLParser::create_with_uncertain_encoding(document, data);
     parser->run(document->url());