diff --git a/files/en-us/mozilla/add-ons/webextensions/manifest.json/theme/index.md b/files/en-us/mozilla/add-ons/webextensions/manifest.json/theme/index.md
index ae5ee8ade4fcd05..48dfb45408f34da 100644
--- a/files/en-us/mozilla/add-ons/webextensions/manifest.json/theme/index.md
+++ b/files/en-us/mozilla/add-ons/webextensions/manifest.json/theme/index.md
@@ -150,27 +150,46 @@ Images should be 200 pixels high to ensure they always fill the header space ver
additional_backgrounds |
- Array of String |
+ Array of String or Object |
Warning: The
- additional_backgrounds property is experimental. It is
- currently accepted in release versions of Firefox, but its behavior
- is subject to change. It is not supported in Firefox for Android.
+ additional_backgrounds property is experimental. It's
+ accepted in release versions of Firefox, but its behavior
+ is subject to change. It's not supported in Firefox for Android.
- An array of URLs for additional background images to be added to the
- header area and displayed behind the
- "theme_frame": image. These images layer the first image
- in the array on top, the last image in the array at the bottom.
+ An array of additional background items to be added to the header area
+ and displayed behind the "theme_frame": image. These items
+ layer the first item in the array on top and the last item at the bottom.
Optional.
- By default all images are anchored to the upper right corner of the
- header area, but their alignment and repeat behavior can be controlled
- by properties of "properties":.
+ Each array item is either a URL string for a background image, or a
+ CSS gradient represented as an object in the form
+ { "GRADIENT_TYPE": "GRADIENT_PARAMS" }, where:
+
+
+ -
+
GRADIENT_TYPE is one of linear-gradient,
+ radial-gradient, conic-gradient,
+ repeating-linear-gradient,
+ repeating-radial-gradient, or
+ repeating-conic-gradient.
+
+ -
+
GRADIENT_PARAMS contains the parameters for that CSS
+ gradient function, as described in
+ CSS gradient values.
+
+
+ CSS gradient objects are supported from Firefox 153.
+
+ By default, all items are anchored to the upper right corner of the
+ header area, but their alignment, repeat, and size behavior can be
+ controlled by "properties":.
|
@@ -1325,6 +1344,25 @@ Additionally, this key accepts various properties that are aliases for one of th
If not specified, defaults to "no-repeat".
+
+ additional_backgrounds_size |
+
+ Array of String
+ |
+
+ Optional
+
+ An array of values defining the size of the corresponding
+ "additional_backgrounds": array item. Accepts the same
+ values as the CSS
+ background-size
+ property, such as "auto", "cover",
+ "contain", or explicit width and height values (for
+ example, "100px 200px").
+
+ If not specified, defaults to "auto".
+ |
+
color_scheme |
@@ -1450,6 +1488,31 @@ It will give you a browser that looks like this:
In this screenshot, `"toolbar_vertical_separator"` is the white vertical line in the URL bar dividing the Reader Mode icon from the other icons.
+This example (Firefox 153+) mixes image backgrounds with a CSS linear gradient:
+
+```json
+"theme": {
+ "images": {
+ "additional_backgrounds": [
+ "background-image1.svg",
+ "background-image2.svg",
+ { "linear-gradient": "to bottom, #FF6BBA -18.096%, #FFC999 50%" }
+ ]
+ },
+ "properties": {
+ "additional_backgrounds_alignment": ["right top", "left top", "right top"],
+ "additional_backgrounds_tiling": ["no-repeat", "no-repeat", "repeat-x"],
+ "additional_backgrounds_size": ["auto", "auto", "auto 144px"]
+ }
+}
+```
+
+This results in:
+
+- `background-image1.svg` displaying at the top right, at its natural size.
+- `background-image2.svg` displaying at the top left, at its natural size.
+- The `linear-gradient` displaying from the top right, tiled horizontally across the header (`repeat-x`), and sized to 144px tall (width is automatic). The gradient transitions from pink (`#FF6BBA`) at the top to peach (`#FFC999`) at the bottom.
+
## Browser compatibility
{{Compat}}
diff --git a/files/en-us/mozilla/firefox/releases/153/index.md b/files/en-us/mozilla/firefox/releases/153/index.md
index bb1c37f0b5d5803..fe3763d296b0dc8 100644
--- a/files/en-us/mozilla/firefox/releases/153/index.md
+++ b/files/en-us/mozilla/firefox/releases/153/index.md
@@ -76,6 +76,7 @@ Firefox 153 is the current [Beta version of Firefox](https://www.firefox.com/en-
- Supports the {{WebExtAPIRef("userScripts.execute()")}} method, enabling extensions to inject user scripts on demand into a tab or frame. Unlike {{WebExtAPIRef("userScripts.register()")}}, this method supports one-off injection of multiple script sources executed in a defined order. ([Firefox bug 1930776](https://bugzil.la/1930776))
- Adds the {{WebExtAPIRef("publicSuffix")}} API, enabling extensions to determine the registrable domain (eTLD+1) and public suffix of a hostname using the browser's built-in [Public Suffix List](https://publicsuffix.org/). The API provides three synchronous methods: {{WebExtAPIRef("publicSuffix.isKnownSuffix()")}}, {{WebExtAPIRef("publicSuffix.getKnownSuffix()")}}, and {{WebExtAPIRef("publicSuffix.getDomain()")}}. ([Firefox bug 1315558](https://bugzil.la/1315558))
- Extension content scripts can now read and modify constructed stylesheets in {{domxref("document.adoptedStyleSheets")}} and {{domxref("ShadowRoot.adoptedStyleSheets")}}, without `.wrappedJSObject`. ([Firefox bug 1751346](https://bugzil.la/1751346))
+- The [`theme`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme) manifest key's `images.additional_backgrounds` property now supports CSS gradients in addition to image URLs. A new `properties.additional_backgrounds_size` property controls the size of each additional background item. ([Firefox bug 2036647](https://bugzil.la/2036647))
- For contextual identities (containers):
- Adds the {{WebExtAPIRef("contextualIdentities.getSupportedColors()")}} and {{WebExtAPIRef("contextualIdentities.getSupportedIcons()")}} methods to retrieve the supported colors and icons, avoiding the need to hardcode those values. ([Firefox bug 2044712](https://bugzil.la/2044712))
- Updates the colors available. `"turquoise"` is renamed to `"cyan"`, `"toolbar"` is renamed to `"gray"`, and `"violet"` is added. The legacy names `"turquoise"` and `"toolbar"` are accepted for backward compatibility. To avoid hardcoding color names, use {{WebExtAPIRef("contextualIdentities.getSupportedColors()")}} to retrieve the available colors. ([Firefox bug 2044354](https://bugzil.la/2044354))
|