diff --git a/files/en-us/mozilla/add-ons/webextensions/api/proxy/proxyinfo/index.md b/files/en-us/mozilla/add-ons/webextensions/api/proxy/proxyinfo/index.md
index e746c1b6d3545cf..761e6548904fc5b 100644
--- a/files/en-us/mozilla/add-ons/webextensions/api/proxy/proxyinfo/index.md
+++ b/files/en-us/mozilla/add-ons/webextensions/api/proxy/proxyinfo/index.md
@@ -17,6 +17,7 @@ Values of this type are objects. They contain the following properties:
     - `"direct"`: don't proxy the request. If this value is given, all other properties of this object are ignored. However, this setting doesn't override any [proxy set by the user](https://support.mozilla.org/en-US/kb/connection-settings-firefox). Use {{WebExtAPIRef("proxy.settings")}} to check whether a manual proxy is being used and, if necessary, monitor those settings for changes using [`BrowserSetting.onChange`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/types/BrowserSetting/onChange).
     - `"http"`: HTTP proxy (or SSL CONNECT for HTTPS)
     - `"https"`: HTTP proxying over TLS connection to proxy
+    - `"masque"`: MASQUE (Multiplexed Application Substrate over QUIC Encryption) proxy
     - `"socks"`: SOCKS v5 proxy
     - `"socks4"`: SOCKS v4 proxy
 
@@ -24,10 +25,12 @@ Values of this type are objects. They contain the following properties:
   - : `string`. The hostname of the proxy server. Mandatory unless `type` is `"direct"`.
 - `port`
   - : `number`. The port number of the proxy server. Mandatory unless `type` is `"direct"`.
-- `username`
-  - : `string`. Username for the proxy service. This is usable with "socks". For HTTP proxy authorizations, use [`webRequest.onAuthRequired`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onAuthRequired).
-- `password`
-  - : `string`. Password for the proxy service. This is usable with "socks". For HTTP proxy authorizations, use [`webRequest.onAuthRequired`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onAuthRequired).
+- `masqueTemplate`
+  - : `string`. The URI template for the MASQUE proxy, starting from the path component of the URI. This must contain the `target_host` and `target_port` template variables as defined in [RFC 9298](https://www.rfc-editor.org/rfc/rfc9298.html#name-client-configuration). For example, `/.well-known/masque/udp/{target_host}/{target_port}/`. Must be set when the proxy type is `"masque"`.
+- `username` {{optional_inline}}
+  - : `string`. Username for the proxy service. This is usable with "socks". For HTTP proxy authorizations, use [`webRequest.onAuthRequired`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onAuthRequired). Must not be set when proxy is `"masque"`.
+- `password` {{optional_inline}}
+  - : `string`. Password for the proxy service. This is usable with "socks". For HTTP proxy authorizations, use [`webRequest.onAuthRequired`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onAuthRequired). Must not be set when proxy is `"masque"`.
 - `proxyDNS`
   - : `boolean`. If true, the proxy server is used to resolve certain DNS queries (only usable with `"socks4"` and `"socks"`). Defaults to `false`.
 - `failoverTimeout`
diff --git a/files/en-us/mozilla/firefox/releases/146/index.md b/files/en-us/mozilla/firefox/releases/146/index.md
index 248ed4ea843197f..03a632813a45129 100644
--- a/files/en-us/mozilla/firefox/releases/146/index.md
+++ b/files/en-us/mozilla/firefox/releases/146/index.md
@@ -77,6 +77,7 @@ Firefox 146 is the current [Nightly version of Firefox](https://www.firefox.com/
 ## Changes for add-on developers
 
 - {{WebExtAPIRef("browsingData.removeLocalStorage")}} and {{WebExtAPIRef("browsingData.remove")}} (when `localStorage` is set in {{WebExtAPIRef("browsingData.DataTypeSet")}}) now delete objects from [`sessionStorage`](/en-US/docs/Web/API/Window/sessionStorage). ([Firefox bug 1886894](https://bugzil.la/1886894))
+- The {{WebExtAPIRef("proxy.onRequest")}} API adds support for MASQUE (Multiplexed Application Substrate over QUIC Encryption) proxies in the {{WebExtAPIRef("proxy.ProxyInfo")}} return type. ([Firefox bug 1988988](https://bugzil.la/1988988) and Firefox bug 1998894](https://bugzil.la/1998894))
 
 <!-- ### Removals -->