| title | Firefox 153 release notes for developers (Nightly) |
|---|---|
| short-title | Firefox 153 (Nightly) |
| slug | Mozilla/Firefox/Releases/153 |
| page-type | firefox-release-notes-active |
| sidebar | firefox |
This article provides information about the changes in Firefox 153 that affect developers. Firefox 153 is the current Nightly version of Firefox and ships on July 21, 2026.
Note
The release notes for this Firefox version are still a work in progress.
- Extensions now require explicit user permission to access
file://URLs. Previously, access to local files was covered by the "Access your data for all websites" host permission. This change introduces a separate "Access local files on your computer" option in the extension's permissions settings (desktop only), and file access is turned off by default for all extensions, including existing ones. The {{WebExtAPIRef("extension.isAllowedFileSchemeAccess()")}} method now correctly returnstrueif the user has granted file scheme access; previously, Firefox always returnedfalse. Additionally, calling {{WebExtAPIRef("devtools.inspectedWindow.eval()")}} onfile://URLs now requires this permission. (Firefox bug 2034168)
These features are shipping in Firefox 153 but are disabled by default.
To experiment with them, search for the appropriate preference on the about:config page and set it to true.
You can find more such features on the Experimental features page.