updated the heading structure of APIs on experimental and moved the C…

…SSPropertyRule & registerProperty to APIs on 128

files/en-us/mozilla/firefox/experimental_features/index.md

@@ -1553,7 +1553,7 @@ Note that, as shown below, the feature is only available on Nightly builds (irre
   </tbody>
 </table>
 
-#### OpenFont COLRv1 fonts
+### OpenFont COLRv1 fonts
 
 This feature provides support for the [OpenFont COLRv1 font specification](https://docs.microsoft.com/en-us/typography/opentype/spec/).
 This enables compression-friendly color vector fonts with gradients, compositing and blending to be loaded using the CSS [`@font-face`](/en-US/docs/Web/CSS/@font-face) rule, or the [CSS Font Loading API](/en-US/docs/Web/API/CSS_Font_Loading_API).
@@ -1595,7 +1595,7 @@ See [Firefox bug 1740530](https://bugzil.la/1740530) for more details.
   </tbody>
 </table>
 
-#### CSS Custom Highlight API
+### CSS Custom Highlight API
 
 The [CSS Custom Highlight API](/en-US/docs/Web/API/CSS_Custom_Highlight_API) provides a mechanism for styling arbitrary text ranges in a document (generalizing the behavior of other highlight pseudo-elements such as {{cssxref('::selection')}}, {{cssxref('::spelling-error')}}, {{cssxref('::grammar-error')}}, and {{cssxref('::target-text')}}).
 The ranges are defined in JavaScript using [`Range`](/en-US/docs/Web/API/Range) instances grouped in a [`Highlight`](/en-US/docs/Web/API/Highlight), and then registered with a name using [`HighlightRegistry`](/en-US/docs/Web/API/HighlightRegistry).

files/en-us/mozilla/firefox/releases/128/index.md

@@ -20,8 +20,6 @@ This article provides information about the changes in Firefox 128 that affect d
 
 - [Relative color syntax](/en-US/docs/Web/CSS/CSS_colors/Relative_colors) is now enabled by default. Relative color syntax allows you to create a color value relative to an origin color, and can allow you to change a color in a different [color space](/en-US/docs/Glossary/Color_space) using [color functions](/en-US/docs/Web/CSS/CSS_colors#functions) ([Firefox bug 1900251](https://bugzil.la/1900251)).
 - The [`content`](/en-US/docs/Web/CSS/content) property now supports [alternative text](/en-US/docs/Web/CSS/content#alternative_text) for content that includes an image. The alternative text is then exposed to the browsers accessibility tree. (See [Firefox bug 1281158](https://bugzil.la/1281158) and [Firefox bug 1896047](https://bugzil.la/1896047)).
-- The [`CSSPropertyRule`](/en-US/docs/Web/API/CSSPropertyRule) is now supported. This allows you to get the values of a [CSS custom property](/en-US/docs/Web/CSS/--*) set in an [`@property`](/en-US/docs/Web/CSS/@property) at-rule, including [`name`](/en-US/docs/Web/API/CSSPropertyRule/name), [`syntax`](/en-US/docs/Web/API/CSSPropertyRule/syntax), [`inherits`](/en-US/docs/Web/API/CSSPropertyRule/inherits) and [`initialValue`](/en-US/docs/Web/API/CSSPropertyRule/initialvalue) ([Firefox bug 1864818](https://bugzil.la/1864818)).
-- The [`registerProperty`](/en-US/docs/Web/API/CSS/registerProperty_static) is now supported. This allows you to define a [CSS custom property](/en-US/docs/Web/CSS/--*) via JavaScript ([Firefox bug 1864818](https://bugzil.la/1864818)).
 
 #### Removals
 
@@ -55,6 +53,8 @@ This article provides information about the changes in Firefox 128 that affect d
   This provides an application with a simple mechanism to know in advance whether playback at the optimal resolution will be allowed, without having to create a media key session or fetch a real license. ([Firefox bug 1878714](https://bugzil.la/1878714)).
 - {{domxref('RTCRtpTransceiver.setCodecPreferences()')}} is now supported for setting the codecs that a WebRTC local peer is able to use for decoding received data, in its preferred codec order. Web applications can use this to cause the remote peer to choose a preferred codec, and to disable the negotiation of specific codecs — including those used for retransmission, redundancy, and forward error correction. ([Firefox bug 1396922](https://bugzil.la/1396922)).
 - Serialization of [declarative shadow DOM](/en-US/docs/Web/API/Web_components/Using_shadow_DOM#declaratively_with_html), including the methods {{domxref('ShadowRoot.getHTML()')}} and {{domxref('Element.getHTML()')}}, and associated properties {{domxref('ShadowRoot.serializable')}} and {{domxref('HTMLTemplateElement.shadowRootSerializable')}}.
+- The [`CSSPropertyRule`](/en-US/docs/Web/API/CSSPropertyRule) is now supported. This allows you to get the values of a [CSS custom property](/en-US/docs/Web/CSS/--*) set in an [`@property`](/en-US/docs/Web/CSS/@property) at-rule, including [`name`](/en-US/docs/Web/API/CSSPropertyRule/name), [`syntax`](/en-US/docs/Web/API/CSSPropertyRule/syntax), [`inherits`](/en-US/docs/Web/API/CSSPropertyRule/inherits) and [`initialValue`](/en-US/docs/Web/API/CSSPropertyRule/initialvalue) ([Firefox bug 1864818](https://bugzil.la/1864818)).
+- The [`registerProperty`](/en-US/docs/Web/API/CSS/registerProperty_static) is now supported. This allows you to define a [CSS custom property](/en-US/docs/Web/CSS/--*) via JavaScript in the same way this can be achieved with the `@property` at-rule in CSS ([Firefox bug 1864818](https://bugzil.la/1864818)).
 
 #### DOM