diff --git a/Userland/Libraries/LibCore/CMakeLists.txt b/Userland/Libraries/LibCore/CMakeLists.txt
index 6dbf1e0a645..a9de2f8de9e 100644
--- a/Userland/Libraries/LibCore/CMakeLists.txt
+++ b/Userland/Libraries/LibCore/CMakeLists.txt
@@ -16,13 +16,6 @@ set(SOURCES
 
 serenity_lib(LibCoreMinimal coreminimal)
 
-if (SERENITYOS)
-    add_library(DynamicLoader_LibCoreArgsParser
-        ArgsParser.cpp
-        Version.cpp)
-    target_link_libraries(DynamicLoader_LibCoreArgsParser PUBLIC DynamicLoader_CompileOptions)
-endif()
-
 set(SOURCES
     AnonymousBuffer.cpp
     Command.cpp
@@ -65,12 +58,7 @@ if (NOT WIN32 AND NOT EMSCRIPTEN)
 endif()
 
 # FIXME: Implement Core::FileWatcher for *BSD and Windows.
-if (SERENITYOS)
-    list(APPEND SOURCES
-        FileWatcherSerenity.cpp
-        Platform/ProcessStatisticsSerenity.cpp
-    )
-elseif (LINUX AND NOT EMSCRIPTEN)
+if (LINUX AND NOT EMSCRIPTEN)
     list(APPEND SOURCES
         FileWatcherLinux.cpp
         Platform/ProcessStatisticsLinux.cpp
diff --git a/Userland/Libraries/LibCore/FileWatcherSerenity.cpp b/Userland/Libraries/LibCore/FileWatcherSerenity.cpp
deleted file mode 100644
index 4e347bd334b..00000000000
--- a/Userland/Libraries/LibCore/FileWatcherSerenity.cpp
+++ /dev/null
@@ -1,222 +0,0 @@
-/*
- * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
- * Copyright (c) 2021, the SerenityOS developers.
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include "FileWatcher.h"
-#include <AK/ByteString.h>
-#include <AK/Debug.h>
-#include <AK/LexicalPath.h>
-#include <AK/NonnullRefPtr.h>
-#include <Kernel/API/InodeWatcherEvent.h>
-#include <Kernel/API/InodeWatcherFlags.h>
-#include <LibCore/Notifier.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-
-#if !defined(AK_OS_SERENITY)
-static_assert(false, "This file must only be used for SerenityOS");
-#endif
-
-namespace Core {
-
-static constexpr unsigned file_watcher_flags_to_inode_watcher_flags(FileWatcherFlags flags)
-{
-    auto result = InodeWatcherFlags::None;
-
-    if (has_flag(flags, FileWatcherFlags::Nonblock))
-        result |= InodeWatcherFlags::Nonblock;
-    if (has_flag(flags, FileWatcherFlags::CloseOnExec))
-        result |= InodeWatcherFlags::CloseOnExec;
-
-    return static_cast<unsigned>(result);
-}
-
-static Optional<FileWatcherEvent> get_event_from_fd(int fd, HashMap<unsigned, ByteString> const& wd_to_path)
-{
-    u8 buffer[MAXIMUM_EVENT_SIZE];
-    int rc = read(fd, &buffer, MAXIMUM_EVENT_SIZE);
-    if (rc == 0) {
-        return {};
-    } else if (rc < 0) {
-        dbgln_if(FILE_WATCHER_DEBUG, "get_event_from_fd: Reading from wd {} failed: {}", fd, strerror(errno));
-        return {};
-    }
-
-    InodeWatcherEvent* event = reinterpret_cast<InodeWatcherEvent*>(buffer);
-    FileWatcherEvent result;
-
-    auto it = wd_to_path.find(event->watch_descriptor);
-    if (it == wd_to_path.end()) {
-        dbgln_if(FILE_WATCHER_DEBUG, "get_event_from_fd: Got an event for a non-existent wd {}?!", event->watch_descriptor);
-        return {};
-    }
-    ByteString const& path = it->value;
-
-    switch (event->type) {
-    case InodeWatcherEvent::Type::ChildCreated:
-        result.type = FileWatcherEvent::Type::ChildCreated;
-        break;
-    case InodeWatcherEvent::Type::ChildDeleted:
-        result.type = FileWatcherEvent::Type::ChildDeleted;
-        break;
-    case InodeWatcherEvent::Type::Deleted:
-        result.type = FileWatcherEvent::Type::Deleted;
-        break;
-    case InodeWatcherEvent::Type::ContentModified:
-        result.type = FileWatcherEvent::Type::ContentModified;
-        break;
-    case InodeWatcherEvent::Type::MetadataModified:
-        result.type = FileWatcherEvent::Type::MetadataModified;
-        break;
-    default:
-        warnln("Unknown event type {} returned by the watch_file descriptor for {}", static_cast<unsigned>(event->type), path);
-        return {};
-    }
-
-    // We trust that the kernel only sends the name when appropriate.
-    if (event->name_length > 0) {
-        ByteString child_name { event->name, event->name_length - 1 };
-        result.event_path = LexicalPath::join(path, child_name).string();
-    } else {
-        result.event_path = path;
-    }
-
-    dbgln_if(FILE_WATCHER_DEBUG, "get_event_from_fd: got event from wd {} on '{}' type {}", fd, result.event_path, result.type);
-    return result;
-}
-
-static ByteString canonicalize_path(ByteString path)
-{
-    if (!path.is_empty() && path[0] == '/')
-        return LexicalPath::canonicalized_path(move(path));
-    char* cwd = getcwd(nullptr, 0);
-    VERIFY(cwd);
-    return LexicalPath::join({ cwd, strlen(cwd) }, move(path)).string();
-}
-
-ErrorOr<bool> FileWatcherBase::add_watch(ByteString path, FileWatcherEvent::Type event_mask)
-{
-    ByteString canonical_path = canonicalize_path(move(path));
-
-    if (m_path_to_wd.find(canonical_path) != m_path_to_wd.end()) {
-        dbgln_if(FILE_WATCHER_DEBUG, "add_watch: path '{}' is already being watched", canonical_path);
-        return false;
-    }
-
-    auto kernel_mask = InodeWatcherEvent::Type::Invalid;
-    if (has_flag(event_mask, FileWatcherEvent::Type::ChildCreated))
-        kernel_mask |= InodeWatcherEvent::Type::ChildCreated;
-    if (has_flag(event_mask, FileWatcherEvent::Type::ChildDeleted))
-        kernel_mask |= InodeWatcherEvent::Type::ChildDeleted;
-    if (has_flag(event_mask, FileWatcherEvent::Type::Deleted))
-        kernel_mask |= InodeWatcherEvent::Type::Deleted;
-    if (has_flag(event_mask, FileWatcherEvent::Type::ContentModified))
-        kernel_mask |= InodeWatcherEvent::Type::ContentModified;
-    if (has_flag(event_mask, FileWatcherEvent::Type::MetadataModified))
-        kernel_mask |= InodeWatcherEvent::Type::MetadataModified;
-
-    int wd = inode_watcher_add_watch(m_watcher_fd, canonical_path.characters(), canonical_path.length(), static_cast<unsigned>(kernel_mask));
-    if (wd < 0)
-        return Error::from_errno(errno);
-
-    m_path_to_wd.set(canonical_path, wd);
-    m_wd_to_path.set(wd, canonical_path);
-
-    dbgln_if(FILE_WATCHER_DEBUG, "add_watch: watching path '{}' on InodeWatcher {} wd {}", canonical_path, m_watcher_fd, wd);
-    return true;
-}
-
-ErrorOr<bool> FileWatcherBase::remove_watch(ByteString path)
-{
-    ByteString canonical_path = canonicalize_path(move(path));
-
-    auto it = m_path_to_wd.find(canonical_path);
-    if (it == m_path_to_wd.end()) {
-        dbgln_if(FILE_WATCHER_DEBUG, "remove_watch: path '{}' is not being watched", canonical_path);
-        return false;
-    }
-
-    if (inode_watcher_remove_watch(m_watcher_fd, it->value) < 0)
-        return Error::from_errno(errno);
-
-    m_path_to_wd.remove(it);
-    m_wd_to_path.remove(it->value);
-
-    dbgln_if(FILE_WATCHER_DEBUG, "remove_watch: stopped watching path '{}' on InodeWatcher {}", canonical_path, m_watcher_fd);
-    return true;
-}
-
-BlockingFileWatcher::BlockingFileWatcher(FileWatcherFlags flags)
-    : FileWatcherBase(create_inode_watcher(file_watcher_flags_to_inode_watcher_flags(flags)))
-{
-    VERIFY(m_watcher_fd != -1);
-    dbgln_if(FILE_WATCHER_DEBUG, "BlockingFileWatcher created with InodeWatcher {}", m_watcher_fd);
-}
-
-BlockingFileWatcher::~BlockingFileWatcher()
-{
-    close(m_watcher_fd);
-}
-
-Optional<FileWatcherEvent> BlockingFileWatcher::wait_for_event()
-{
-    dbgln_if(FILE_WATCHER_DEBUG, "BlockingFileWatcher::wait_for_event()");
-
-    auto maybe_event = get_event_from_fd(m_watcher_fd, m_wd_to_path);
-    if (!maybe_event.has_value())
-        return maybe_event;
-
-    auto event = maybe_event.release_value();
-    if (event.type == FileWatcherEvent::Type::Deleted) {
-        auto result = remove_watch(event.event_path);
-        if (result.is_error()) {
-            dbgln_if(FILE_WATCHER_DEBUG, "wait_for_event: {}", result.error());
-        }
-    }
-
-    return event;
-}
-
-ErrorOr<NonnullRefPtr<FileWatcher>> FileWatcher::create(FileWatcherFlags flags)
-{
-    auto watcher_fd = create_inode_watcher(file_watcher_flags_to_inode_watcher_flags(flags | FileWatcherFlags::CloseOnExec));
-    if (watcher_fd < 0)
-        return Error::from_errno(errno);
-
-    auto notifier = Notifier::construct(watcher_fd, Notifier::Type::Read);
-    return adopt_ref(*new FileWatcher(watcher_fd, move(notifier)));
-}
-
-FileWatcher::FileWatcher(int watcher_fd, NonnullRefPtr<Notifier> notifier)
-    : FileWatcherBase(watcher_fd)
-    , m_notifier(move(notifier))
-{
-    m_notifier->on_activation = [this] {
-        auto maybe_event = get_event_from_fd(m_notifier->fd(), m_wd_to_path);
-        if (maybe_event.has_value()) {
-            auto event = maybe_event.value();
-            on_change(event);
-
-            if (event.type == FileWatcherEvent::Type::Deleted) {
-                auto result = remove_watch(event.event_path);
-                if (result.is_error()) {
-                    dbgln_if(FILE_WATCHER_DEBUG, "on_ready_to_read: {}", result.error());
-                }
-            }
-        }
-    };
-}
-
-FileWatcher::~FileWatcher()
-{
-    m_notifier->on_activation = nullptr;
-    close(m_notifier->fd());
-    dbgln_if(FILE_WATCHER_DEBUG, "Stopped watcher at fd {}", m_notifier->fd());
-}
-
-}
diff --git a/Userland/Libraries/LibCore/Platform/ProcessStatisticsSerenity.cpp b/Userland/Libraries/LibCore/Platform/ProcessStatisticsSerenity.cpp
deleted file mode 100644
index 32f2a7fe956..00000000000
--- a/Userland/Libraries/LibCore/Platform/ProcessStatisticsSerenity.cpp
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <AK/Platform.h>
-
-#if !defined(AK_OS_SERENITY)
-#    error "This file is for Serenity OS only"
-#endif
-
-#include <LibCore/File.h>
-#include <LibCore/Platform/ProcessStatistics.h>
-#include <LibCore/ProcessStatisticsReader.h>
-
-namespace Core::Platform {
-
-ErrorOr<void> update_process_statistics(ProcessStatistics& statistics)
-{
-    static auto proc_all_file = TRY(Core::File::open("/sys/kernel/processes"sv, Core::File::OpenMode::Read));
-
-    auto const all_processes = TRY(Core::ProcessStatisticsReader::get_all(*proc_all_file, false));
-
-    auto const total_time_scheduled = all_processes.total_time_scheduled;
-    auto const total_time_scheduled_diff = total_time_scheduled - statistics.total_time_scheduled;
-    statistics.total_time_scheduled = total_time_scheduled;
-
-    for (auto& process : statistics.processes) {
-        auto it = all_processes.processes.find_if([&](auto& entry) { return entry.pid == process->pid; });
-        if (!it.is_end()) {
-            process->memory_usage_bytes = it->amount_resident;
-
-            u64 time_process = 0;
-            for (auto& thread : it->threads) {
-                time_process += thread.time_user + thread.time_kernel;
-            }
-            u64 time_scheduled_diff = time_process - process->time_spent_in_process;
-
-            process->time_spent_in_process = time_process;
-            process->cpu_percent = 0.0;
-            if (total_time_scheduled_diff > 0) {
-                process->cpu_percent = static_cast<float>((time_scheduled_diff * 1000) / total_time_scheduled_diff) / 10.0f;
-            }
-        } else {
-            process->memory_usage_bytes = 0;
-            process->cpu_percent = 0.0;
-            process->time_spent_in_process = 0;
-        }
-    }
-
-    return {};
-}
-
-}
diff --git a/Userland/Libraries/LibRegex/C/Regex.cpp b/Userland/Libraries/LibRegex/C/Regex.cpp
deleted file mode 100644
index 0b8a988ca5e..00000000000
--- a/Userland/Libraries/LibRegex/C/Regex.cpp
+++ /dev/null
@@ -1,221 +0,0 @@
-/*
- * Copyright (c) 2020, Emanuel Sprung <emanuel.sprung@gmail.com>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <AK/ByteString.h>
-#include <AK/StringBuilder.h>
-#include <AK/Variant.h>
-#include <LibRegex/Regex.h>
-#include <ctype.h>
-#include <regex.h>
-#include <stdio.h>
-#include <string.h>
-
-#ifndef AK_OS_SERENITY
-#    error "This file is intended for use on Serenity only to implement POSIX regex.h"
-#endif
-
-struct internal_regex_t {
-    u8 cflags;
-    u8 eflags;
-    Optional<Variant<NonnullOwnPtr<Regex<PosixExtended>>, NonnullOwnPtr<Regex<PosixBasic>>>> re;
-    size_t re_pat_errpos;
-    ReError re_pat_err;
-    ByteString re_pat;
-};
-
-static internal_regex_t* impl_from(regex_t* re)
-{
-    if (!re)
-        return nullptr;
-
-    return reinterpret_cast<internal_regex_t*>(re->__data);
-}
-
-static internal_regex_t const* impl_from(regex_t const* re)
-{
-    return impl_from(const_cast<regex_t*>(re));
-}
-
-extern "C" {
-
-int regcomp(regex_t* reg, char const* pattern, int cflags)
-{
-    if (!reg)
-        return REG_ESPACE;
-
-    // Note that subsequent uses of regcomp() without regfree() _will_ leak memory
-    // This could've been prevented if libc provided a reginit() or similar, but it does not.
-    reg->__data = new internal_regex_t { 0, 0, {}, 0, ReError::REG_NOERR, {} };
-
-    auto* preg = impl_from(reg);
-    bool is_extended = cflags & REG_EXTENDED;
-
-    preg->cflags = cflags;
-
-    ByteString pattern_str(pattern);
-    if (is_extended)
-        preg->re = make<Regex<PosixExtended>>(pattern_str, PosixOptions {} | (PosixFlags)cflags | PosixFlags::SkipTrimEmptyMatches);
-    else
-        preg->re = make<Regex<PosixBasic>>(pattern_str, PosixOptions {} | (PosixFlags)cflags | PosixFlags::SkipTrimEmptyMatches);
-
-    auto parser_result = preg->re->visit([](auto& re) { return re->parser_result; });
-
-    if (parser_result.error != regex::Error::NoError) {
-        preg->re_pat_errpos = parser_result.error_token.position();
-        preg->re_pat_err = (ReError)parser_result.error;
-        preg->re_pat = pattern;
-
-        dbgln("Have Error: {}", (int)parser_result.error);
-
-        return (ReError)parser_result.error;
-    }
-
-    reg->re_nsub = parser_result.capture_groups_count;
-
-    return REG_NOERR;
-}
-
-int regexec(regex_t const* reg, char const* string, size_t nmatch, regmatch_t pmatch[], int eflags)
-{
-    auto const* preg = impl_from(reg);
-
-    if (!preg->re.has_value() || preg->re_pat_err) {
-        if (preg->re_pat_err)
-            return preg->re_pat_err;
-        return REG_BADPAT;
-    }
-
-    RegexResult result;
-    StringView string_view { string, strlen(string) };
-    if (eflags & REG_SEARCH)
-        result = preg->re->visit([&](auto& re) { return re->search(string_view, PosixOptions {} | (PosixFlags)eflags); });
-    else
-        result = preg->re->visit([&](auto& re) { return re->match(string_view, PosixOptions {} | (PosixFlags)eflags); });
-
-    if (result.success) {
-        auto capture_groups_count = preg->re->visit([](auto& re) { return re->parser_result.capture_groups_count; });
-        auto size = result.matches.size();
-        if (size && nmatch && pmatch) {
-            pmatch[0].rm_cnt = size;
-
-            size_t match_index { 0 };
-            for (size_t i = 0; i < size; ++i) {
-                pmatch[match_index].rm_so = result.matches.at(i).global_offset;
-                pmatch[match_index].rm_eo = pmatch[match_index].rm_so + result.matches.at(i).view.length();
-                if (match_index > 0)
-                    pmatch[match_index].rm_cnt = result.capture_group_matches.size();
-
-                ++match_index;
-                if (match_index >= nmatch)
-                    return REG_NOERR;
-
-                if (i < result.capture_group_matches.size()) {
-                    auto capture_groups_size = result.capture_group_matches.at(i).size();
-                    for (size_t j = 0; j < capture_groups_count; ++j) {
-                        if (j >= capture_groups_size || !result.capture_group_matches.at(i).at(j).view.length()) {
-                            pmatch[match_index].rm_so = -1;
-                            pmatch[match_index].rm_eo = -1;
-                            pmatch[match_index].rm_cnt = 0;
-                        } else {
-                            pmatch[match_index].rm_so = result.capture_group_matches.at(i).at(j).global_offset;
-                            pmatch[match_index].rm_eo = pmatch[match_index].rm_so + result.capture_group_matches.at(i).at(j).view.length();
-                            pmatch[match_index].rm_cnt = 1;
-                        }
-
-                        ++match_index;
-                        if (match_index >= nmatch)
-                            return REG_NOERR;
-                    }
-                }
-            }
-
-            if (match_index < nmatch) {
-                for (size_t i = match_index; i < nmatch; ++i) {
-                    pmatch[i].rm_so = -1;
-                    pmatch[i].rm_eo = -1;
-                    pmatch[i].rm_cnt = 0;
-                }
-            }
-        }
-        return REG_NOERR;
-    }
-
-    if (nmatch && pmatch) {
-        pmatch[0].rm_so = -1;
-        pmatch[0].rm_eo = -1;
-        pmatch[0].rm_cnt = 0;
-    }
-
-    return REG_NOMATCH;
-}
-
-static StringView get_error(ReError errcode)
-{
-    switch (errcode) {
-    case REG_NOERR:
-        return "No error"sv;
-    case REG_NOMATCH:
-        return "regexec() failed to match."sv;
-    case REG_BADPAT:
-        return "Invalid regular expression."sv;
-    case REG_ECOLLATE:
-        return "Invalid collating element referenced."sv;
-    case REG_ECTYPE:
-        return "Invalid character class type referenced."sv;
-    case REG_EESCAPE:
-        return "Trailing \\ in pattern."sv;
-    case REG_ESUBREG:
-        return "Number in \\digit invalid or in error."sv;
-    case REG_EBRACK:
-        return "[ ] imbalance."sv;
-    case REG_EPAREN:
-        return "\\( \\) or ( ) imbalance."sv;
-    case REG_EBRACE:
-        return "\\{ \\} imbalance."sv;
-    case REG_BADBR:
-        return "Content of \\{ \\} invalid: not a number, number too large, more than two numbers, first larger than second."sv;
-    case REG_ERANGE:
-        return "Invalid endpoint in range expression."sv;
-    case REG_ESPACE:
-        return "Out of memory."sv;
-    case REG_BADRPT:
-        return "?, * or + not preceded by valid regular expression."sv;
-    case REG_ENOSYS:
-        return "The implementation does not support the function."sv;
-    case REG_EMPTY_EXPR:
-        return "Empty expression provided"sv;
-    }
-    return {};
-}
-
-size_t regerror(int errcode, regex_t const* reg, char* errbuf, size_t errbuf_size)
-{
-    ByteString error;
-    auto const* preg = impl_from(reg);
-
-    if (!preg)
-        error = get_error((ReError)errcode);
-    else
-        error = preg->re->visit([&](auto& re) { return re->error_string(get_error(preg->re_pat_err)); });
-
-    if (!errbuf_size)
-        return error.length();
-
-    if (!error.copy_characters_to_buffer(errbuf, errbuf_size))
-        return 0;
-
-    return error.length();
-}
-
-void regfree(regex_t* reg)
-{
-    auto* preg = impl_from(reg);
-    if (preg) {
-        delete preg;
-        reg->__data = nullptr;
-    }
-}
-}
diff --git a/Userland/Libraries/LibWebView/CMakeLists.txt b/Userland/Libraries/LibWebView/CMakeLists.txt
index d30fae96192..497715439b0 100644
--- a/Userland/Libraries/LibWebView/CMakeLists.txt
+++ b/Userland/Libraries/LibWebView/CMakeLists.txt
@@ -21,10 +21,6 @@ set(SOURCES
 
 set(GENERATED_SOURCES ${CURRENT_LIB_GENERATED})
 
-if (SERENITYOS)
-    list(APPEND SOURCES OutOfProcessWebView.cpp)
-endif()
-
 embed_as_string_view(
     "NativeStyleSheetSource.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/Native.css"
@@ -53,18 +49,16 @@ serenity_lib(LibWebView webview)
 target_link_libraries(LibWebView PRIVATE LibCore LibFileSystem LibGfx LibIPC LibProtocol LibJS LibWeb LibSQL LibUnicode LibURL)
 target_compile_definitions(LibWebView PRIVATE ENABLE_PUBLIC_SUFFIX=$<BOOL:${ENABLE_PUBLIC_SUFFIX_DOWNLOAD}>)
 
-if (NOT SERENITYOS)
-    foreach(header ${GENERATED_SOURCES})
-        get_filename_component(extension ${header} EXT)
-        if (NOT "${extension}" STREQUAL ".h")
-            continue()
-        endif()
+foreach(header ${GENERATED_SOURCES})
+    get_filename_component(extension ${header} EXT)
+    if (NOT "${extension}" STREQUAL ".h")
+        continue()
+    endif()
 
-        get_filename_component(subdirectory ${header} DIRECTORY)
-        string(REGEX REPLACE "^\\.\\./\\.\\./" "" subdirectory "${subdirectory}")
+    get_filename_component(subdirectory ${header} DIRECTORY)
+    string(REGEX REPLACE "^\\.\\./\\.\\./" "" subdirectory "${subdirectory}")
 
-        install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${header}" DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${subdirectory}")
-    endforeach()
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${header}" DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${subdirectory}")
+endforeach()
 
-    install(FILES "${SERENITY_PROJECT_ROOT}/Userland/Services/RequestServer/ConnectionCache.h" DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/RequestServer")
-endif()
+install(FILES "${SERENITY_PROJECT_ROOT}/Userland/Services/RequestServer/ConnectionCache.h" DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/RequestServer")