diff --git a/Userland/Libraries/LibWeb/Animations/Animation.idl b/Userland/Libraries/LibWeb/Animations/Animation.idl
index 3f6c5384b0d..fc1579f636c 100644
--- a/Userland/Libraries/LibWeb/Animations/Animation.idl
+++ b/Userland/Libraries/LibWeb/Animations/Animation.idl
@@ -31,7 +31,7 @@ interface Animation : EventTarget {
     undefined updatePlaybackRate(double playbackRate);
     undefined reverse();
     undefined persist();
-    // FIXME: [CEReactions] undefined commitStyles();
+    [FIXME, CEReactions] undefined commitStyles();
 };
 
 // https://www.w3.org/TR/web-animations-1/#the-animationplaystate-enumeration
diff --git a/Userland/Libraries/LibWeb/CSS/CSSImportRule.idl b/Userland/Libraries/LibWeb/CSS/CSSImportRule.idl
index bf0984de1d3..fd8b073129b 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSImportRule.idl
+++ b/Userland/Libraries/LibWeb/CSS/CSSImportRule.idl
@@ -8,6 +8,6 @@ interface CSSImportRule : CSSRule {
     readonly attribute USVString href;
     // FIXME: [SameObject, PutForwards=mediaText] readonly attribute MediaList media;
     [SameObject, ImplementedAs=style_sheet_for_bindings] readonly attribute CSSStyleSheet styleSheet;
-    // FIXME: readonly attribute CSSOMString? layerName;
-    // FIXME: readonly attribute CSSOMString? supportsText;
+    [FIXME] readonly attribute CSSOMString? layerName;
+    [FIXME] readonly attribute CSSOMString? supportsText;
 };
diff --git a/Userland/Libraries/LibWeb/CSS/CSSKeyframesRule.idl b/Userland/Libraries/LibWeb/CSS/CSSKeyframesRule.idl
index ba38a1ab980..f1aab1c311b 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSKeyframesRule.idl
+++ b/Userland/Libraries/LibWeb/CSS/CSSKeyframesRule.idl
@@ -5,11 +5,11 @@
 [Exposed=Window]
 interface CSSKeyframesRule : CSSRule {
     attribute CSSOMString name;
-    // FIXME: readonly attribute CSSRuleList cssRules;
+    [FIXME] readonly attribute CSSRuleList cssRules;
     readonly attribute unsigned long length;
 
     getter CSSKeyframeRule (unsigned long index);
-    // FIXME: undefined appendRule(CSSOMString rule);
-    // FIXME: undefined deleteRule(CSSOMString select);
-    // FIXME: CSSKeyframeRule? findRule(CSSOMString select);
+    [FIXME] undefined appendRule(CSSOMString rule);
+    [FIXME] undefined deleteRule(CSSOMString select);
+    [FIXME] CSSKeyframeRule? findRule(CSSOMString select);
 };
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.idl b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.idl
index d2eb2060f03..be762f4a0fd 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.idl
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.idl
@@ -13,7 +13,7 @@ interface CSSStyleDeclaration {
     [CEReactions] undefined setProperty(CSSOMString property, [LegacyNullToEmptyString] CSSOMString value, optional [LegacyNullToEmptyString] CSSOMString priority = "");
     [CEReactions] CSSOMString removeProperty(CSSOMString property);
 
-    // FIXME: readonly attribute CSSRule? parentRule;
+    [FIXME] readonly attribute CSSRule? parentRule;
     // FIXME: [CEReactions] attribute [LegacyNullToEmptyString] CSSOMString cssFloat;
 
 };
diff --git a/Userland/Libraries/LibWeb/CSS/FontFaceSet.idl b/Userland/Libraries/LibWeb/CSS/FontFaceSet.idl
index 7668f349c7f..55d0aee8921 100644
--- a/Userland/Libraries/LibWeb/CSS/FontFaceSet.idl
+++ b/Userland/Libraries/LibWeb/CSS/FontFaceSet.idl
@@ -20,8 +20,8 @@ interface FontFaceSet : EventTarget {
 
     // FIXME: setlike<FontFace>;
     FontFaceSet add(FontFace font);
-    // FIXME: boolean delete(FontFace font);
-    // FIXME:  clear();
+    [FIXME] boolean delete(FontFace font);
+    [FIXME] undefined clear();
 
     // events for when loading state changes
     // FIXME: attribute EventHandler onloading;
diff --git a/Userland/Libraries/LibWeb/Clipboard/Clipboard.idl b/Userland/Libraries/LibWeb/Clipboard/Clipboard.idl
index d1f1c0bc975..bd44a262ea2 100644
--- a/Userland/Libraries/LibWeb/Clipboard/Clipboard.idl
+++ b/Userland/Libraries/LibWeb/Clipboard/Clipboard.idl
@@ -5,8 +5,8 @@
 // https://w3c.github.io/clipboard-apis/#clipboard
 [SecureContext, Exposed=Window]
 interface Clipboard : EventTarget {
-    // FIXME: Promise<ClipboardItems> read();
-    // FIXME: Promise<DOMString> readText();
-    // FIXME: Promise<undefined> write(ClipboardItems data);
+    [FIXME] Promise<ClipboardItems> read();
+    [FIXME] Promise<DOMString> readText();
+    [FIXME] Promise<undefined> write(ClipboardItems data);
     Promise<undefined> writeText(DOMString data);
 };
diff --git a/Userland/Libraries/LibWeb/Crypto/SubtleCrypto.idl b/Userland/Libraries/LibWeb/Crypto/SubtleCrypto.idl
index fc72bfccc9a..78002aec0d3 100644
--- a/Userland/Libraries/LibWeb/Crypto/SubtleCrypto.idl
+++ b/Userland/Libraries/LibWeb/Crypto/SubtleCrypto.idl
@@ -59,6 +59,6 @@ interface SubtleCrypto {
     Promise<CryptoKey> importKey(KeyFormat format, (BufferSource or JsonWebKey) keyData,  AlgorithmIdentifier algorithm, boolean extractable, sequence<KeyUsage> keyUsages);
     Promise<any> exportKey(KeyFormat format, CryptoKey key);
 
-    // FIXME: Promise<any> wrapKey(KeyFormat format, CryptoKey key, CryptoKey wrappingKey, AlgorithmIdentifier wrapAlgorithm);
-    // FIXME: Promise<CryptoKey> unwrapKey(KeyFormat format, BufferSource wrappedKey, CryptoKey unwrappingKey, AlgorithmIdentifier unwrapAlgorithm, AlgorithmIdentifier unwrappedKeyAlgorithm, boolean extractable, sequence<KeyUsage> keyUsages);
+    [FIXME] Promise<any> wrapKey(KeyFormat format, CryptoKey key, CryptoKey wrappingKey, AlgorithmIdentifier wrapAlgorithm);
+    [FIXME] Promise<CryptoKey> unwrapKey(KeyFormat format, BufferSource wrappedKey, CryptoKey unwrappingKey, AlgorithmIdentifier unwrapAlgorithm, AlgorithmIdentifier unwrappedKeyAlgorithm, boolean extractable, sequence<KeyUsage> keyUsages);
 };
diff --git a/Userland/Libraries/LibWeb/DOM/Element.idl b/Userland/Libraries/LibWeb/DOM/Element.idl
index e0484481f41..334d2703f69 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.idl
+++ b/Userland/Libraries/LibWeb/DOM/Element.idl
@@ -75,7 +75,7 @@ interface Element : Node {
     DOMRectList getClientRects();
     DOMRect getBoundingClientRect();
 
-    // FIXME: boolean checkVisibility(optional CheckVisibilityOptions options = {});
+    [FIXME] boolean checkVisibility(optional CheckVisibilityOptions options = {});
 
     undefined scrollIntoView(optional (boolean or ScrollIntoViewOptions) arg = {});
     undefined scroll(optional ScrollToOptions options = {});
diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawPath.idl b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawPath.idl
index 0d78c777cb4..75d7ada6e46 100644
--- a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawPath.idl
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawPath.idl
@@ -18,8 +18,8 @@ interface mixin CanvasDrawPath {
     // FIXME: `DOMString` should be `CanvasFillRule`
     undefined clip(Path2D path, optional DOMString fillRule = "nonzero");
 
-    // FIXME: boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
-    // FIXME: boolean isPointInPath(Path2D path, unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
-    // FIXME: boolean isPointInStroke(unrestricted double x, unrestricted double y);
-    // FIXME: boolean isPointInStroke(Path2D path, unrestricted double x, unrestricted double y);
+    [FIXME] boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
+    [FIXME] boolean isPointInPath(Path2D path, unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
+    [FIXME] boolean isPointInStroke(unrestricted double x, unrestricted double y);
+    [FIXME] boolean isPointInStroke(Path2D path, unrestricted double x, unrestricted double y);
 };
diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasImageData.idl b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasImageData.idl
index 7cc5c9dbaa4..4709ff43310 100644
--- a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasImageData.idl
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasImageData.idl
@@ -3,10 +3,10 @@
 // https://html.spec.whatwg.org/multipage/canvas.html#canvasimagedata
 interface mixin CanvasImageData {
     ImageData createImageData([EnforceRange] long sw, [EnforceRange] long sh, optional ImageDataSettings settings = {});
-    // FIXME: ImageData createImageData(ImageData imagedata);
+    [FIXME] ImageData createImageData(ImageData imagedata);
 
     ImageData getImageData([EnforceRange] long sx, [EnforceRange] long sy, [EnforceRange] long sw, [EnforceRange] long sh, optional ImageDataSettings settings = {});
 
     undefined putImageData(ImageData imagedata, [EnforceRange] long dx, [EnforceRange] long dy);
-    // FIXME: undefined putImageData(ImageData imagedata, [EnforceRange] long dx, [EnforceRange] long dy, [EnforceRange] long dirtyX, [EnforceRange] long dirtyY, [EnforceRange] long dirtyWidth, [EnforceRange] long dirtyHeight);
+    [FIXME] undefined putImageData(ImageData imagedata, [EnforceRange] long dx, [EnforceRange] long dy, [EnforceRange] long dirtyX, [EnforceRange] long dirtyY, [EnforceRange] long dirtyWidth, [EnforceRange] long dirtyHeight);
 };
diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasPathDrawingStyles.idl b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasPathDrawingStyles.idl
index 4e6f7e717ef..648bb2afda5 100644
--- a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasPathDrawingStyles.idl
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasPathDrawingStyles.idl
@@ -9,7 +9,7 @@ interface mixin CanvasPathDrawingStyles {
     // FIXME: attribute CanvasLineJoin lineJoin;
     // FIXME: attribute unrestricted double miterLimit;
 
-    // FIXME: undefined setLineDash(sequence<unrestricted double> segments);
-    // FIXME: sequence<unrestricted double> getLineDash();
+    [FIXME] undefined setLineDash(sequence<unrestricted double> segments);
+    [FIXME] sequence<unrestricted double> getLineDash();
     // FIXME: attribute unrestricted double lineDashOffset;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/DataTransfer.idl b/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
index cad37aa4ab7..2c0710a53be 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
+++ b/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
@@ -6,14 +6,14 @@ interface DataTransfer {
     // FIXME: attribute DOMString dropEffect;
     // FIXME: attribute DOMString effectAllowed;
 
-    // FIXME: [SameObject] readonly attribute DataTransferItemList items;
+    [FIXME, SameObject] readonly attribute DataTransferItemList items;
 
-    // FIXME: undefined setDragImage(Element image, long x, long y);
+    [FIXME] undefined setDragImage(Element image, long x, long y);
 
     // old interface
-    // FIXME: readonly attribute FrozenArray<DOMString> types;
-    // FIXME: DOMString getData(DOMString format);
-    // FIXME: undefined setData(DOMString format, DOMString data);
-    // FIXME: undefined clearData(optional DOMString format);
-    // FIXME: [SameObject] readonly attribute FileList files;
+    [FIXME] readonly attribute FrozenArray<DOMString> types;
+    [FIXME] DOMString getData(DOMString format);
+    [FIXME] undefined setData(DOMString format, DOMString data);
+    [FIXME] undefined clearData(optional DOMString format);
+    [FIXME, SameObject] readonly attribute FileList files;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLButtonElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLButtonElement.idl
index e7b8dae094e..47f6769d78d 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLButtonElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLButtonElement.idl
@@ -24,12 +24,12 @@ interface HTMLButtonElement : HTMLElement {
     [CEReactions, Reflect, Enumerated=ButtonTypeState] attribute DOMString type;
     [CEReactions, Reflect] attribute DOMString value;
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
-    // FIXME: boolean checkValidity();
-    // FIXME: boolean reportValidity();
-    // FIXME: undefined setCustomValidity(DOMString error);
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
+    [FIXME] boolean checkValidity();
+    [FIXME] boolean reportValidity();
+    [FIXME] undefined setCustomValidity(DOMString error);
 
     readonly attribute NodeList labels;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLElement.idl
index 73545f3cb59..5b2086a9133 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLElement.idl
@@ -31,9 +31,9 @@ interface HTMLElement : Element {
     // FIXME: ElementInternals attachInternals();
 
     // The popover API
-    // FIXME: undefined showPopover();
-    // FIXME: undefined hidePopover();
-    // FIXME: boolean togglePopover(optional boolean force);
+    [FIXME] undefined showPopover();
+    [FIXME] undefined hidePopover();
+    [FIXME] boolean togglePopover(optional boolean force);
     // FIXME: [CEReactions] attribute DOMString? popover;
 
     // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLEmbedElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLEmbedElement.idl
index ef309c89191..ca00cb572db 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLEmbedElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLEmbedElement.idl
@@ -10,7 +10,7 @@ interface HTMLEmbedElement : HTMLElement {
     [CEReactions, Reflect] attribute DOMString type;
     [CEReactions, Reflect] attribute DOMString width;
     [CEReactions, Reflect] attribute DOMString height;
-    // FIXME: Document? getSVGDocument();
+    [FIXME] Document? getSVGDocument();
 
     // Obsolete
     [CEReactions, Reflect] attribute DOMString align;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.idl
index 9e133e70d50..ce8e4b09d4e 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.idl
@@ -14,10 +14,10 @@ interface HTMLFieldSetElement : HTMLElement {
 
     [SameObject] readonly attribute HTMLCollection elements;
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: [SameObject] readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
-    // FIXME: boolean checkValidity();
-    // FIXME: boolean reportValidity();
-    // FIXME: undefined setCustomValidity(DOMString error);
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME, SameObject] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
+    [FIXME] boolean checkValidity();
+    [FIXME] boolean reportValidity();
+    [FIXME] undefined setCustomValidity(DOMString error);
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFrameElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLFrameElement.idl
index dc4def2d8d7..c9d54fd5863 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFrameElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFrameElement.idl
@@ -12,8 +12,8 @@ interface HTMLFrameElement : HTMLElement {
     [CEReactions, Reflect=frameborder] attribute DOMString frameBorder;
     [CEReactions, Reflect=longdesc] attribute DOMString longDesc;
     // FIXME: [CEReactions] attribute boolean noResize;
-    // FIXME: readonly attribute Document? contentDocument;
-    // FIXME: readonly attribute WindowProxy? contentWindow;
+    [FIXME] readonly attribute Document? contentDocument;
+    [FIXME] readonly attribute WindowProxy? contentWindow;
 
     // FIXME: [CEReactions] attribute [LegacyNullToEmptyString] DOMString marginHeight;
     // FIXME: [CEReactions] attribute [LegacyNullToEmptyString] DOMString marginWidth;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.idl
index 7027cb511ba..da30c723985 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.idl
@@ -18,13 +18,13 @@ interface HTMLImageElement : HTMLElement {
     readonly attribute unsigned long naturalWidth;
     readonly attribute unsigned long naturalHeight;
     readonly attribute boolean complete;
-    // FIXME: readonly attribute USVString currentSrc;
+    [FIXME] readonly attribute USVString currentSrc;
     // FIXME: [CEReactions] attribute DOMString referrerPolicy;
     // FIXME: [CEReactions] attribute DOMString decoding;
     // FIXME: [CEReactions] attribute DOMString loading;
     // FIXME: [CEReactions] attribute DOMString fetchPriority;
 
-    // FIXME: Promise<undefined> decode();
+    [FIXME] Promise<undefined> decode();
 
     // Obsolete
     [CEReactions, Reflect] attribute DOMString name;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.idl
index 9c103c8c6cb..f9c5e76b385 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.idl
@@ -23,7 +23,7 @@ interface HTMLInputElement : HTMLElement {
     [CEReactions, Reflect=formtarget] attribute DOMString formTarget;
     // FIXME: [CEReactions] attribute unsigned long height;
     attribute boolean indeterminate;
-    // FIXME: readonly attribute HTMLDataListElement? list;
+    [FIXME] readonly attribute HTMLDataListElement? list;
     [CEReactions, Reflect] attribute DOMString max;
     [CEReactions] attribute long maxLength;
     [CEReactions, Reflect] attribute DOMString min;
@@ -47,9 +47,9 @@ interface HTMLInputElement : HTMLElement {
     undefined stepUp(optional long n = 1);
     undefined stepDown(optional long n = 1);
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
     boolean checkValidity();
     boolean reportValidity();
     undefined setCustomValidity(DOMString error);
@@ -60,8 +60,8 @@ interface HTMLInputElement : HTMLElement {
     // FIXME: attribute unsigned long? selectionStart;
     // FIXME: attribute unsigned long? selectionEnd;
     // FIXME: attribute DOMString? selectionDirection;
-    // FIXME: undefined setRangeText(DOMString replacement);
-    // FIXME: undefined setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
+    [FIXME] undefined setRangeText(DOMString replacement);
+    [FIXME] undefined setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
     undefined setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
 
     undefined showPicker();
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
index fa12118ced2..45c6f0a787b 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
@@ -18,7 +18,6 @@ interface HTMLMarqueeElement : HTMLElement {
     // FIXME: [CEReactions] attribute unsigned long vspace;
     [CEReactions, Reflect] attribute DOMString width;
 
-    // FIXME: undefined start();
-    // FIXME: undefined stop();
-
+    [FIXME] undefined start();
+    [FIXME] undefined stop();
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl
index cbc20ba9052..26d4a2f3230 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl
@@ -51,8 +51,8 @@ interface HTMLMediaElement : HTMLElement {
     // FIXME: attribute double defaultPlaybackRate;
     // FIXME: attribute double playbackRate;
     // FIXME: attribute boolean preservesPitch;
-    // FIXME: readonly attribute TimeRanges played;
-    // FIXME: readonly attribute TimeRanges seekable;
+    [FIXME] readonly attribute TimeRanges played;
+    [FIXME] readonly attribute TimeRanges seekable;
     readonly attribute boolean ended;
     [Reflect, CEReactions] attribute boolean autoplay;
     [Reflect, CEReactions] attribute boolean loop;
@@ -68,7 +68,7 @@ interface HTMLMediaElement : HTMLElement {
     // tracks
     [SameObject] readonly attribute AudioTrackList audioTracks;
     [SameObject] readonly attribute VideoTrackList videoTracks;
-    // FIXME: [SameObject] readonly attribute TextTrackList textTracks;
-    // FIXME: TextTrack addTextTrack(TextTrackKind kind, optional DOMString label = "", optional DOMString language = "");
+    [FIXME, SameObject] readonly attribute TextTrackList textTracks;
+    [FIXME] TextTrack addTextTrack(TextTrackKind kind, optional DOMString label = "", optional DOMString language = "");
 
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.idl
index aeae525564f..dc9c146ff15 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.idl
@@ -17,12 +17,12 @@ interface HTMLObjectElement : HTMLElement {
     readonly attribute WindowProxy? contentWindow;
     Document? getSVGDocument();
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
-    // FIXME: boolean checkValidity();
-    // FIXME: boolean reportValidity();
-    // FIXME: undefined setCustomValidity(DOMString error);
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
+    [FIXME] boolean checkValidity();
+    [FIXME] boolean reportValidity();
+    [FIXME] undefined setCustomValidity(DOMString error);
 
     // Obsolete
     [CEReactions, Reflect] attribute DOMString align;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLOutputElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLOutputElement.idl
index 00f8a4efed0..22bec6ba433 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLOutputElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLOutputElement.idl
@@ -14,12 +14,12 @@ interface HTMLOutputElement : HTMLElement {
     [CEReactions] attribute DOMString defaultValue;
     [CEReactions] attribute DOMString value;
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
-    // FIXME: boolean checkValidity();
-    // FIXME: boolean reportValidity();
-    // FIXME: undefined setCustomValidity(DOMString error);
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
+    [FIXME] boolean checkValidity();
+    [FIXME] boolean reportValidity();
+    [FIXME] undefined setCustomValidity(DOMString error);
 
     readonly attribute NodeList labels;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLSelectElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLSelectElement.idl
index 92cde398156..e2aed45b46e 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLSelectElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLSelectElement.idl
@@ -24,18 +24,18 @@ interface HTMLSelectElement : HTMLElement {
     [CEReactions] undefined add((HTMLOptionElement or HTMLOptGroupElement) element, optional (HTMLElement or long)? before = null);
     [CEReactions] undefined remove(); // ChildNode overload
     [CEReactions] undefined remove(long index);
-    // FIXME: [CEReactions] setter undefined (unsigned long index, HTMLOptionElement? option);
+    [FIXME, CEReactions] setter undefined (unsigned long index, HTMLOptionElement? option);
 
     [SameObject] readonly attribute HTMLCollection selectedOptions;
     attribute long selectedIndex;
     attribute DOMString value;
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
-    // FIXME: boolean checkValidity();
-    // FIXME: boolean reportValidity();
-    // FIXME: undefined setCustomValidity(DOMString error);
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
+    [FIXME] boolean checkValidity();
+    [FIXME] boolean reportValidity();
+    [FIXME] undefined setCustomValidity(DOMString error);
 
     readonly attribute NodeList labels;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.idl
index 8fac4631a2e..c20dfbe3420 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.idl
@@ -9,7 +9,7 @@ interface HTMLTableCellElement : HTMLElement {
     [CEReactions] attribute unsigned long colSpan;
     [CEReactions] attribute unsigned long rowSpan;
     [CEReactions, Reflect] attribute DOMString headers;
-    // FIXME: readonly attribute long cellIndex;
+    [FIXME] readonly attribute long cellIndex;
 
     // FIXME: [CEReactions] attribute DOMString scope; // only conforming for th elements
     [CEReactions, Reflect] attribute DOMString abbr;  // only conforming for th elements
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.idl
index be322031bfd..ad16d7fd008 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.idl
@@ -25,9 +25,9 @@ interface HTMLTextAreaElement : HTMLElement {
     [LegacyNullToEmptyString] attribute DOMString value;
     readonly attribute unsigned long textLength;
 
-    // FIXME: readonly attribute boolean willValidate;
-    // FIXME: readonly attribute ValidityState validity;
-    // FIXME: readonly attribute DOMString validationMessage;
+    [FIXME] readonly attribute boolean willValidate;
+    [FIXME] readonly attribute ValidityState validity;
+    [FIXME] readonly attribute DOMString validationMessage;
     boolean checkValidity();
     boolean reportValidity();
     undefined setCustomValidity(DOMString error);
@@ -38,7 +38,7 @@ interface HTMLTextAreaElement : HTMLElement {
     attribute unsigned long selectionStart;
     attribute unsigned long selectionEnd;
     // FIXME: attribute DOMString selectionDirection;
-    // FIXME: undefined setRangeText(DOMString replacement);
-    // FIXME: undefined setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
-    // FIXME: undefined setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
+    [FIXME] undefined setRangeText(DOMString replacement);
+    [FIXME] undefined setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
+    [FIXME] undefined setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTrackElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLTrackElement.idl
index d5855aa60d8..c1836a1cc96 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTrackElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTrackElement.idl
@@ -16,8 +16,8 @@ interface HTMLTrackElement : HTMLElement {
     // FIXME: [const unsigned short LOADING = 1;
     // FIXME: [const unsigned short LOADED = 2;
     // FIXME: [const unsigned short ERROR = 3;
-    // FIXME: [readonly attribute unsigned short readyState;
+    [FIXME] readonly attribute unsigned short readyState;
 
-    // FIXME: [readonly attribute TextTrack track;
+    [FIXME] readonly attribute TextTrack track;
 
 };
diff --git a/Userland/Libraries/LibWeb/HTML/ImageData.idl b/Userland/Libraries/LibWeb/HTML/ImageData.idl
index 2f462944b13..ffd2d826d2d 100644
--- a/Userland/Libraries/LibWeb/HTML/ImageData.idl
+++ b/Userland/Libraries/LibWeb/HTML/ImageData.idl
@@ -13,5 +13,5 @@ interface ImageData {
     readonly attribute unsigned long width;
     readonly attribute unsigned long height;
     readonly attribute Uint8ClampedArray data;
-    // FIXME: readonly attribute PredefinedColorSpace colorSpace;
+    [FIXME] readonly attribute PredefinedColorSpace colorSpace;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/Location.idl b/Userland/Libraries/LibWeb/HTML/Location.idl
index aa377143d59..d79cb6eb70f 100644
--- a/Userland/Libraries/LibWeb/HTML/Location.idl
+++ b/Userland/Libraries/LibWeb/HTML/Location.idl
@@ -15,5 +15,5 @@ interface Location { // but see also additional creation steps and overridden in
     [LegacyUnforgeable] undefined replace(USVString url);
     [LegacyUnforgeable] undefined reload();
 
-    // TODO: [LegacyUnforgeable, SameObject] readonly attribute DOMStringList ancestorOrigins;
+    [FIXME, LegacyUnforgeable, SameObject] readonly attribute DOMStringList ancestorOrigins;
 };
diff --git a/Userland/Libraries/LibWeb/HTML/Navigator.idl b/Userland/Libraries/LibWeb/HTML/Navigator.idl
index 7a95283344b..f0c1ff1fb00 100644
--- a/Userland/Libraries/LibWeb/HTML/Navigator.idl
+++ b/Userland/Libraries/LibWeb/HTML/Navigator.idl
@@ -24,8 +24,8 @@ interface Navigator {
 
 // https://html.spec.whatwg.org/multipage/system-state.html#navigatorcontentutils
 interface mixin NavigatorContentUtils {
-    // FIXME: [SecureContext] undefined registerProtocolHandler(DOMString scheme, USVString url);
-    // FIXME: [SecureContext] undefined unregisterProtocolHandler(DOMString scheme, USVString url);
+    [FIXME, SecureContext] undefined registerProtocolHandler(DOMString scheme, USVString url);
+    [FIXME, SecureContext] undefined unregisterProtocolHandler(DOMString scheme, USVString url);
 };
 
 // https://html.spec.whatwg.org/multipage/system-state.html#navigatorcookies
diff --git a/Userland/Libraries/LibWeb/HTML/PopStateEvent.idl b/Userland/Libraries/LibWeb/HTML/PopStateEvent.idl
index 6df7c00c244..23e42d644e5 100644
--- a/Userland/Libraries/LibWeb/HTML/PopStateEvent.idl
+++ b/Userland/Libraries/LibWeb/HTML/PopStateEvent.idl
@@ -6,7 +6,7 @@ interface PopStateEvent : Event {
   constructor(DOMString type, optional PopStateEventInit eventInitDict = {});
 
   readonly attribute any state;
-  // FIXME: readonly attribute boolean hasUAVisualTransition;
+  [FIXME] readonly attribute boolean hasUAVisualTransition;
 };
 
 dictionary PopStateEventInit : EventInit {
diff --git a/Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.idl b/Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.idl
index 06861329147..36a47862683 100644
--- a/Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.idl
+++ b/Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.idl
@@ -17,7 +17,7 @@ interface mixin WindowOrWorkerGlobalScope {
     readonly attribute boolean isSecureContext;
     readonly attribute boolean crossOriginIsolated;
 
-    // FIXME: undefined reportError(any e);
+    [FIXME] undefined reportError(any e);
 
     // base64 utility methods
     DOMString btoa(DOMString data);
diff --git a/Userland/Libraries/LibWeb/IndexedDB/IDBFactory.idl b/Userland/Libraries/LibWeb/IndexedDB/IDBFactory.idl
index a273ff54645..f65b3b44977 100644
--- a/Userland/Libraries/LibWeb/IndexedDB/IDBFactory.idl
+++ b/Userland/Libraries/LibWeb/IndexedDB/IDBFactory.idl
@@ -5,11 +5,11 @@
 interface IDBFactory {
     [NewObject] IDBOpenDBRequest open(DOMString name,
                                       optional [EnforceRange] unsigned long long version);
-    // FIXME: [NewObject] IDBOpenDBRequest deleteDatabase(DOMString name);
+    [FIXME, NewObject] IDBOpenDBRequest deleteDatabase(DOMString name);
 
-    // FIXME: Promise<sequence<IDBDatabaseInfo>> databases();
+    [FIXME] Promise<sequence<IDBDatabaseInfo>> databases();
 
-    // FIXME: short cmp(any first, any second);
+    [FIXME] short cmp(any first, any second);
 };
 
 dictionary IDBDatabaseInfo {
diff --git a/Userland/Libraries/LibWeb/IndexedDB/IDBRequest.idl b/Userland/Libraries/LibWeb/IndexedDB/IDBRequest.idl
index 4e0b1643c06..867f16a5098 100644
--- a/Userland/Libraries/LibWeb/IndexedDB/IDBRequest.idl
+++ b/Userland/Libraries/LibWeb/IndexedDB/IDBRequest.idl
@@ -3,11 +3,11 @@
 // https://w3c.github.io/IndexedDB/#idbrequest
 [Exposed=(Window,Worker)]
 interface IDBRequest : EventTarget {
-    // FIXME: readonly attribute any result;
-    // FIXME: readonly attribute DOMException? error;
-    // FIXME: readonly attribute (IDBObjectStore or IDBIndex or IDBCursor)? source;
-    // FIXME: readonly attribute IDBTransaction? transaction;
-    // FIXME: readonly attribute IDBRequestReadyState readyState;
+    [FIXME] readonly attribute any result;
+    [FIXME] readonly attribute DOMException? error;
+    [FIXME] readonly attribute (IDBObjectStore or IDBIndex or IDBCursor)? source;
+    [FIXME] readonly attribute IDBTransaction? transaction;
+    [FIXME] readonly attribute IDBRequestReadyState readyState;
 
     // Event handlers:
     // FIXME: attribute EventHandler onsuccess;
diff --git a/Userland/Libraries/LibWeb/IntersectionObserver/IntersectionObserver.idl b/Userland/Libraries/LibWeb/IntersectionObserver/IntersectionObserver.idl
index 66d5db6af35..86f5e288624 100644
--- a/Userland/Libraries/LibWeb/IntersectionObserver/IntersectionObserver.idl
+++ b/Userland/Libraries/LibWeb/IntersectionObserver/IntersectionObserver.idl
@@ -11,7 +11,7 @@ callback IntersectionObserverCallback = undefined (sequence<IntersectionObserver
 interface IntersectionObserver {
     constructor(IntersectionObserverCallback callback, optional IntersectionObserverInit options = {});
     readonly attribute (Element or Document)? root;
-    // FIXME: readonly attribute DOMString rootMargin;
+    [FIXME] readonly attribute DOMString rootMargin;
     // FIXME: `sequence<double>` should be `FrozenArray<double>`
     readonly attribute sequence<double> thresholds;
     undefined observe(Element target);
diff --git a/Userland/Libraries/LibWeb/SVG/SVGClipPathElement.idl b/Userland/Libraries/LibWeb/SVG/SVGClipPathElement.idl
index 2103734e9d4..babf2e02c63 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGClipPathElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGClipPathElement.idl
@@ -4,7 +4,7 @@
 [Exposed=Window]
 interface SVGClipPathElement : SVGElement {
 
-    // FIXME: readonly attribute SVGAnimatedEnumeration clipPathUnits;
-    // FIXME: readonly attribute SVGAnimatedTransformList transform;
+    [FIXME] readonly attribute SVGAnimatedEnumeration clipPathUnits;
+    [FIXME] readonly attribute SVGAnimatedTransformList transform;
 
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGFitToViewBox.idl b/Userland/Libraries/LibWeb/SVG/SVGFitToViewBox.idl
index c92b537d4a4..17a57aca342 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGFitToViewBox.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGFitToViewBox.idl
@@ -3,5 +3,5 @@
 // https://svgwg.org/svg2-draft/types.html#InterfaceSVGFitToViewBox
 interface mixin SVGFitToViewBox {
     [SameObject, ImplementedAs=view_box_for_bindings] readonly attribute SVGAnimatedRect viewBox;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedPreserveAspectRatio preserveAspectRatio;
+    [FIXME, SameObject] readonly attribute SVGAnimatedPreserveAspectRatio preserveAspectRatio;
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.idl b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.idl
index 625373fbda3..30dbacb836c 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.idl
@@ -10,9 +10,9 @@ interface SVGGradientElement : SVGElement {
     const unsigned short SVG_SPREADMETHOD_REFLECT = 2;
     const unsigned short SVG_SPREADMETHOD_REPEAT = 3;
 
-    // FIXME: [SameObject] readonly attribute SVGAnimatedEnumeration gradientUnits;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedTransformList gradientTransform;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedEnumeration spreadMethod;
+    [FIXME, SameObject] readonly attribute SVGAnimatedEnumeration gradientUnits;
+    [FIXME, SameObject] readonly attribute SVGAnimatedTransformList gradientTransform;
+    [FIXME, SameObject] readonly attribute SVGAnimatedEnumeration spreadMethod;
 
 };
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.idl b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.idl
index 14c9b9efe37..037c6ebcf0a 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.idl
@@ -14,6 +14,6 @@ interface SVGGraphicsElement : SVGElement {
   [SameObject] readonly attribute SVGAnimatedTransformList transform;
 
   DOMRect getBBox(optional SVGBoundingBoxOptions options = {});
-  // FIXME: DOMMatrix? getCTM();
-  // FIXME: DOMMatrix? getScreenCTM();
+  [FIXME] DOMMatrix? getCTM();
+  [FIXME] DOMMatrix? getScreenCTM();
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.idl b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.idl
index 5aa4beed6cb..ac396c0997c 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.idl
@@ -3,12 +3,10 @@
 // https://drafts.fxtf.org/css-masking/#InterfaceSVGMaskElement
 [Exposed=Window]
 interface SVGMaskElement : SVGElement {
-
-    // FIXME: readonly attribute SVGAnimatedEnumeration maskUnits;
-    // FIXME: readonly attribute SVGAnimatedEnumeration maskContentUnits;
-    // FIXME: readonly attribute SVGAnimatedLength x;
-    // FIXME: readonly attribute SVGAnimatedLength y;
-    // FIXME: readonly attribute SVGAnimatedLength width;
-    // FIXME: readonly attribute SVGAnimatedLength height;
-
+    [FIXME] readonly attribute SVGAnimatedEnumeration maskUnits;
+    [FIXME] readonly attribute SVGAnimatedEnumeration maskContentUnits;
+    [FIXME] readonly attribute SVGAnimatedLength x;
+    [FIXME] readonly attribute SVGAnimatedLength y;
+    [FIXME] readonly attribute SVGAnimatedLength width;
+    [FIXME] readonly attribute SVGAnimatedLength height;
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.idl b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.idl
index 4c55e4447f8..02c31b5763f 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.idl
@@ -22,12 +22,12 @@ interface SVGSVGElement : SVGGraphicsElement {
 
   // FIMXE: SVGNumber createSVGNumber();
   SVGLength createSVGLength();
-  // FIXME: SVGAngle createSVGAngle();
+  [FIXME] SVGAngle createSVGAngle();
   DOMPoint createSVGPoint();
   DOMMatrix createSVGMatrix();
   DOMRect createSVGRect();
   SVGTransform createSVGTransform();
-  // FIXME: SVGTransform createSVGTransformFromMatrix(optional DOMMatrix2DInit matrix = {});
+  [FIXME] SVGTransform createSVGTransformFromMatrix(optional DOMMatrix2DInit matrix = {});
 
   Element getElementById(DOMString elementId);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTextContentElement.idl b/Userland/Libraries/LibWeb/SVG/SVGTextContentElement.idl
index 4a8155efb97..42901628900 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTextContentElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGTextContentElement.idl
@@ -9,17 +9,17 @@ interface SVGTextContentElement : SVGGraphicsElement {
     const unsigned short LENGTHADJUST_SPACING = 1;
     const unsigned short LENGTHADJUST_SPACINGANDGLYPHS = 2;
 
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLength textLength;
-    // FIXME:[SameObject] readonly attribute SVGAnimatedEnumeration lengthAdjust;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLength textLength;
+    [FIXME, SameObject] readonly attribute SVGAnimatedEnumeration lengthAdjust;
 
     long getNumberOfChars();
-    // FIXME: float getComputedTextLength();
-    // FIXME: float getSubStringLength(unsigned long charnum, unsigned long nchars);
+    [FIXME] float getComputedTextLength();
+    [FIXME] float getSubStringLength(unsigned long charnum, unsigned long nchars);
     DOMPoint getStartPositionOfChar(unsigned long charnum);
-    // FIXME: DOMPoint getEndPositionOfChar(unsigned long charnum);
-    // FIXME: DOMRect getExtentOfChar(unsigned long charnum);
-    // FIXME: float getRotationOfChar(unsigned long charnum);
-    // FIXME: long getCharNumAtPosition(optional DOMPointInit point = {});
-    // FIXME: undefined selectSubString(unsigned long charnum, unsigned long nchars);
+    [FIXME] DOMPoint getEndPositionOfChar(unsigned long charnum);
+    [FIXME] DOMRect getExtentOfChar(unsigned long charnum);
+    [FIXME] float getRotationOfChar(unsigned long charnum);
+    [FIXME] long getCharNumAtPosition(optional DOMPointInit point = {});
+    [FIXME] undefined selectSubString(unsigned long charnum, unsigned long nchars);
 
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTextPathElement.idl b/Userland/Libraries/LibWeb/SVG/SVGTextPathElement.idl
index 2e578afe65a..1926896cc89 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTextPathElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGTextPathElement.idl
@@ -14,9 +14,9 @@ interface SVGTextPathElement : SVGTextContentElement {
     const unsigned short TEXTPATH_SPACINGTYPE_AUTO = 1;
     const unsigned short TEXTPATH_SPACINGTYPE_EXACT = 2;
 
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLength startOffset;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedEnumeration method;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedEnumeration spacing;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLength startOffset;
+    [FIXME, SameObject] readonly attribute SVGAnimatedEnumeration method;
+    [FIXME, SameObject] readonly attribute SVGAnimatedEnumeration spacing;
 };
 
 SVGTextPathElement includes SVGURIReference;
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.idl b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.idl
index 671f077f932..b20642cbde0 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.idl
@@ -3,9 +3,9 @@
 // https://svgwg.org/svg2-draft/text.html#InterfaceSVGTextPositioningElement
 [Exposed=Window]
 interface SVGTextPositioningElement : SVGTextContentElement {
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLengthList x;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLengthList y;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLengthList dx;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedLengthList dy;
-    // FIXME: [SameObject] readonly attribute SVGAnimatedNumberList rotate;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLengthList x;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLengthList y;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLengthList dx;
+    [FIXME, SameObject] readonly attribute SVGAnimatedLengthList dy;
+    [FIXME, SameObject] readonly attribute SVGAnimatedNumberList rotate;
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTransform.idl b/Userland/Libraries/LibWeb/SVG/SVGTransform.idl
index 76327b4a78b..865177bf2f4 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTransform.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGTransform.idl
@@ -11,10 +11,10 @@ interface SVGTransform {
     const unsigned short SVG_TRANSFORM_SKEWY = 6;
 
     readonly attribute unsigned short type;
-    // FIXME: [SameObject] readonly attribute DOMMatrix matrix;
+    [FIXME, SameObject] readonly attribute DOMMatrix matrix;
     readonly attribute float angle;
 
-    // FIXME: undefined setMatrix(optional DOMMatrix2DInit matrix = {});
+    [FIXME] undefined setMatrix(optional DOMMatrix2DInit matrix = {});
     undefined setTranslate(float tx, float ty);
     undefined setScale(float sx, float sy);
     undefined setRotate(float angle, float cx, float cy);
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTransformList.idl b/Userland/Libraries/LibWeb/SVG/SVGTransformList.idl
index 0bfdda1d3c0..2baf34e0b99 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTransformList.idl
+++ b/Userland/Libraries/LibWeb/SVG/SVGTransformList.idl
@@ -3,19 +3,19 @@
 // https://svgwg.org/svg2-draft/single-page.html#coords-InterfaceSVGTransformList
 [Exposed=Window]
 interface SVGTransformList {
-  // FIXME: readonly attribute unsigned long length;
-  // FIXME: readonly attribute unsigned long numberOfItems;
+  [FIXME] readonly attribute unsigned long length;
+  [FIXME] readonly attribute unsigned long numberOfItems;
 
-  // FIXME: undefined clear();
+  [FIXME] undefined clear();
   // FIXME: SVGTransform initialize(SVGTransform newItem);
   getter SVGTransform getItem(unsigned long index);
-  // FIXME: SVGTransform insertItemBefore(SVGTransform newItem, unsigned long index);
-  // FIXME: SVGTransform replaceItem(SVGTransform newItem, unsigned long index);
-  // FIXME: SVGTransform removeItem(unsigned long index);
+  [FIXME] SVGTransform insertItemBefore(SVGTransform newItem, unsigned long index);
+  [FIXME] SVGTransform replaceItem(SVGTransform newItem, unsigned long index);
+  [FIXME] SVGTransform removeItem(unsigned long index);
   SVGTransform appendItem(SVGTransform newItem);
   // FIXME: setter undefined (unsigned long index, SVGTransform newItem);
 
   // Additional methods not common to other list interfaces.
-  // FIXME: SVGTransform createSVGTransformFromMatrix(optional DOMMatrix2DInit matrix = {});
-  // FIXME: SVGTransform? consolidate();
+  [FIXME] SVGTransform createSVGTransformFromMatrix(optional DOMMatrix2DInit matrix = {});
+  [FIXME] SVGTransform? consolidate();
 };
diff --git a/Userland/Libraries/LibWeb/Streams/ReadableStream.idl b/Userland/Libraries/LibWeb/Streams/ReadableStream.idl
index c62d3f97f56..f58795e6fd8 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableStream.idl
+++ b/Userland/Libraries/LibWeb/Streams/ReadableStream.idl
@@ -29,7 +29,7 @@ dictionary ReadableStreamGetReaderOptions {
 interface ReadableStream {
     constructor(optional object underlyingSource, optional QueuingStrategy strategy = {});
 
-    // FIXME: static ReadableStream from(any asyncIterable);
+    [FIXME] static ReadableStream from(any asyncIterable);
 
     readonly attribute boolean locked;
 
diff --git a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
index 7134d33244a..76ddcbf195f 100644
--- a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
+++ b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
@@ -29,7 +29,7 @@ interface MouseEvent : UIEvent {
     readonly attribute short button;
     readonly attribute unsigned short buttons;
 
-    // FIXME: readonly attribute EventTarget? relatedTarget;
+    [FIXME] readonly attribute EventTarget? relatedTarget;
 
     boolean getModifierState(DOMString keyArg);
 };
diff --git a/Userland/Libraries/LibWeb/UIEvents/PointerEvent.idl b/Userland/Libraries/LibWeb/UIEvents/PointerEvent.idl
index 81ea58cb2c2..b99851848a9 100644
--- a/Userland/Libraries/LibWeb/UIEvents/PointerEvent.idl
+++ b/Userland/Libraries/LibWeb/UIEvents/PointerEvent.idl
@@ -33,6 +33,6 @@ interface PointerEvent : MouseEvent {
     readonly attribute double azimuthAngle;
     readonly attribute DOMString pointerType;
     readonly attribute boolean isPrimary;
-    // FIXME: [SecureContext] sequence<PointerEvent> getCoalescedEvents();
-    // FIXME: sequence<PointerEvent> getPredictedEvents();
+    [FIXME, SecureContext] sequence<PointerEvent> getCoalescedEvents();
+    [FIXME] sequence<PointerEvent> getPredictedEvents();
 };
diff --git a/Userland/Libraries/LibWeb/WebAssembly/Module.idl b/Userland/Libraries/LibWeb/WebAssembly/Module.idl
index eb03880b86e..04f191c63b3 100644
--- a/Userland/Libraries/LibWeb/WebAssembly/Module.idl
+++ b/Userland/Libraries/LibWeb/WebAssembly/Module.idl
@@ -21,7 +21,7 @@ dictionary ModuleImportDescriptor {
 interface Module {
     constructor(BufferSource bytes);
 
-    // FIXME: static sequence<ModuleExportDescriptor> exports(Module moduleObject);
-    // FIXME: static sequence<ModuleImportDescriptor> imports(Module moduleObject);
-    // FIXME: static sequence<ArrayBuffer> customSections(Module moduleObject, DOMString sectionName);
+    [FIXME] static sequence<ModuleExportDescriptor> exports(Module moduleObject);
+    [FIXME] static sequence<ModuleImportDescriptor> imports(Module moduleObject);
+    [FIXME] static sequence<ArrayBuffer> customSections(Module moduleObject, DOMString sectionName);
 };
diff --git a/Userland/Libraries/LibWeb/WebAudio/AudioContext.idl b/Userland/Libraries/LibWeb/WebAudio/AudioContext.idl
index e8d44a65496..b8cee9b2e5d 100644
--- a/Userland/Libraries/LibWeb/WebAudio/AudioContext.idl
+++ b/Userland/Libraries/LibWeb/WebAudio/AudioContext.idl
@@ -13,10 +13,10 @@ interface AudioContext : BaseAudioContext {
     Promise<undefined> resume ();
     Promise<undefined> suspend ();
     Promise<undefined> close ();
-    // FIXME: MediaElementAudioSourceNode createMediaElementSource (HTMLMediaElement mediaElement);
-    // FIXME: MediaStreamAudioSourceNode createMediaStreamSource (MediaStream mediaStream);
-    // FIXME: MediaStreamTrackAudioSourceNode createMediaStreamTrackSource (MediaStreamTrack mediaStreamTrack);
-    // FIXME: MediaStreamAudioDestinationNode createMediaStreamDestination ();
+    [FIXME] MediaElementAudioSourceNode createMediaElementSource (HTMLMediaElement mediaElement);
+    [FIXME] MediaStreamAudioSourceNode createMediaStreamSource (MediaStream mediaStream);
+    [FIXME] MediaStreamTrackAudioSourceNode createMediaStreamTrackSource (MediaStreamTrack mediaStreamTrack);
+    [FIXME] MediaStreamAudioDestinationNode createMediaStreamDestination ();
 };
 
 dictionary AudioContextOptions {
diff --git a/Userland/Libraries/LibWeb/WebAudio/AudioNode.idl b/Userland/Libraries/LibWeb/WebAudio/AudioNode.idl
index 593f60b3f27..b602cd8c847 100644
--- a/Userland/Libraries/LibWeb/WebAudio/AudioNode.idl
+++ b/Userland/Libraries/LibWeb/WebAudio/AudioNode.idl
@@ -38,8 +38,8 @@ interface AudioNode : EventTarget {
     undefined disconnect(AudioParam destinationParam);
     undefined disconnect(AudioParam destinationParam, unsigned long output);
     readonly attribute BaseAudioContext context;
-    // FIXME: readonly attribute unsigned long numberOfInputs;
-    // FIXME: readonly attribute unsigned long numberOfOutputs;
+    [FIXME] readonly attribute unsigned long numberOfInputs;
+    [FIXME] readonly attribute unsigned long numberOfOutputs;
     // FIXME: attribute unsigned long channelCount;
     // FIXME: attribute ChannelCountMode channelCountMode;
     // FIXME: attribute ChannelInterpretation channelInterpretation;
diff --git a/Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.idl b/Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.idl
index a52ac7b5c7e..a8f7aaa049d 100644
--- a/Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.idl
+++ b/Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.idl
@@ -16,30 +16,30 @@ interface BaseAudioContext : EventTarget {
     // FIXME: readonly attribute AudioDestinationNode destination;
     readonly attribute float sampleRate;
     readonly attribute double currentTime;
-    // FIXME: readonly attribute AudioListener listener;
+    [FIXME] readonly attribute AudioListener listener;
     readonly attribute AudioContextState state;
     // FIXME: [SameObject, SecureContext]
-    // readonly attribute AudioWorklet audioWorklet;
+    [FIXME] readonly attribute AudioWorklet audioWorklet;
     attribute EventHandler onstatechange;
 
-    // FIXME: AnalyserNode createAnalyser ();
-    // FIXME: BiquadFilterNode createBiquadFilter ();
-    // FIXME: AudioBuffer createBuffer (unsigned long numberOfChannels, unsigned long length, float sampleRate);
-    // FIXME: AudioBufferSourceNode createBufferSource ();
-    // FIXME: ChannelMergerNode createChannelMerger (optional unsigned long numberOfInputs = 6);
-    // FIXME: ChannelSplitterNode createChannelSplitter (optional unsigned long numberOfOutputs = 6);
-    // FIXME: ConstantSourceNode createConstantSource ();
-    // FIXME: ConvolverNode createConvolver ();
-    // FIXME: DelayNode createDelay (optional double maxDelayTime = 1.0);
+    [FIXME] AnalyserNode createAnalyser ();
+    [FIXME] BiquadFilterNode createBiquadFilter ();
+    [FIXME] AudioBuffer createBuffer (unsigned long numberOfChannels, unsigned long length, float sampleRate);
+    [FIXME] AudioBufferSourceNode createBufferSource ();
+    [FIXME] ChannelMergerNode createChannelMerger (optional unsigned long numberOfInputs = 6);
+    [FIXME] ChannelSplitterNode createChannelSplitter (optional unsigned long numberOfOutputs = 6);
+    [FIXME] ConstantSourceNode createConstantSource ();
+    [FIXME] ConvolverNode createConvolver ();
+    [FIXME] DelayNode createDelay (optional double maxDelayTime = 1.0);
     DynamicsCompressorNode createDynamicsCompressor();
-    // FIXME: GainNode createGain ();
-    // FIXME: IIRFilterNode createIIRFilter (sequence<double> feedforward, sequence<double> feedback);
+    [FIXME] GainNode createGain ();
+    [FIXME] IIRFilterNode createIIRFilter (sequence<double> feedforward, sequence<double> feedback);
     OscillatorNode createOscillator();
-    // FIXME: PannerNode createPanner ();
-    // FIXME: PeriodicWave createPeriodicWave (sequence<float> real, sequence<float> imag, optional PeriodicWaveConstraints constraints = {});
-    // FIXME: ScriptProcessorNode createScriptProcessor(optional unsigned long bufferSize = 0, optional unsigned long numberOfInputChannels = 2, optional unsigned long numberOfOutputChannels = 2);
-    // FIXME: StereoPannerNode createStereoPanner ();
-    // FIXME: WaveShaperNode createWaveShaper ();
+    [FIXME] PannerNode createPanner ();
+    [FIXME] PeriodicWave createPeriodicWave (sequence<float> real, sequence<float> imag, optional PeriodicWaveConstraints constraints = {});
+    [FIXME] ScriptProcessorNode createScriptProcessor(optional unsigned long bufferSize = 0, optional unsigned long numberOfInputChannels = 2, optional unsigned long numberOfOutputChannels = 2);
+    [FIXME] StereoPannerNode createStereoPanner ();
+    [FIXME] WaveShaperNode createWaveShaper ();
 
-    // FIXME: Promise<AudioBuffer> decodeAudioData (ArrayBuffer audioData, optional DecodeSuccessCallback? successCallback, optional DecodeErrorCallback? errorCallback);
+    [FIXME] Promise<AudioBuffer> decodeAudioData (ArrayBuffer audioData, optional DecodeSuccessCallback? successCallback, optional DecodeErrorCallback? errorCallback);
 };
diff --git a/Userland/Libraries/LibWeb/WebAudio/OscillatorNode.idl b/Userland/Libraries/LibWeb/WebAudio/OscillatorNode.idl
index 38063796d6b..7652226bb97 100644
--- a/Userland/Libraries/LibWeb/WebAudio/OscillatorNode.idl
+++ b/Userland/Libraries/LibWeb/WebAudio/OscillatorNode.idl
@@ -24,6 +24,6 @@ interface OscillatorNode : AudioScheduledSourceNode {
     constructor(BaseAudioContext context, optional OscillatorOptions options = {});
     attribute OscillatorType type;
     readonly attribute AudioParam frequency;
-    // FIXME: readonly attribute AudioParam detune;
-    // FIXME: undefined setPeriodicWave(PeriodicWave periodicWave);
+    [FIXME] readonly attribute AudioParam detune;
+    [FIXME] undefined setPeriodicWave(PeriodicWave periodicWave);
 };
diff --git a/Userland/Libraries/LibWeb/WebSockets/WebSocket.idl b/Userland/Libraries/LibWeb/WebSockets/WebSocket.idl
index 21c4116acf5..2ecef757841 100644
--- a/Userland/Libraries/LibWeb/WebSockets/WebSocket.idl
+++ b/Userland/Libraries/LibWeb/WebSockets/WebSocket.idl
@@ -16,7 +16,7 @@ interface WebSocket : EventTarget {
     const unsigned short CLOSING = 2;
     const unsigned short CLOSED = 3;
     readonly attribute unsigned short readyState;
-    // FIXME: readonly attribute unsigned long long bufferedAmount;
+    [FIXME] readonly attribute unsigned long long bufferedAmount;
 
     // networking
     attribute EventHandler onopen;