See what landed recently in Firefox Nightly!

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

148.0a1 Firefox Nightly

December 8, 2025

Version 148.0a1, first offered to Nightly channel users on December 8, 2025

Firefox Nightly gets updated every day and as a consequence, the release notes for the Nightly channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.

Warning: Features listed here may or may not make a final release of Firefox.

In addition to these release notes, you can follow ongoing development on our @FirefoxNightly Bluesky account, our @FirefoxNightly Mastodon account as well as read our Nightly Blog.

You can interact with other Firefox Nightly users and give your feedback to Mozilla staff in the Nightly Matrix room on chat.mozilla.org.

New

  • Starting with Firefox 146, you can now right-click any tab and add a quick note to it, making it easier to keep track of what you were doing without needing an extension.

    Bug 1994520

  • Starting with Firefox 147, Nightly and Beta builds (b6 and earlier) have improved support for screen readers accessing mathematical formulas embedded in PDFs.

    Bug 1937438

Developer

  • Developer Information

  • Starting with Firefox 146, added support for calling showPicker() on text-based <input> elements with an associated <datalist>, allowing programmatic display of autofill suggestions for users on Nightly builds or Beta builds (b6 and earlier).

    Bug 1998670

Web Platform

  • Starting with Firefox 147, Nightly and Beta builds (b6 and earlier) now support the Sanitizer API, which provides new methods for HTML manipulation. The element.setHTML() method enables developers to insert HTML content similarly to element.innerHTML, but without the security vulnerabilities such as cross-site scripting (XSS). A complementary method, document.parseHTML(), is also available for parsing HTML safely.

    Bug 1954437

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