Tab groups begin rolling out today

Version 137.0, first offered to Release channel users on April 1, 2025

New
Tab groups begin rolling out today! Stay productive and organized with less effort by grouping related tabs together. One simple way to create a group is to drag a tab onto another, pause until you see a highlight, then drop to create the group. Groups can be named, color-coded, and are always saved. You can close a group and reopen it later.

Firefox Address Bar Refresh 2025 - new ways to search for things new, previously viewed, and more - all from the address bar:

Features
Unified Search Button: A new, easy-to-access button in the address bar helps you switch between search engines and search modes with ease. This feature brings the simplicity of mobile Firefox to your desktop experience.

Search Term Persistence: Now when you refine a search in the address bar, the original term sticks around, making it easier to adjust your queries and find exactly what you're looking for.

Secondary Action Buttons: Suggestions for common Firefox features.

Contextual Search Mode: Firefox detects if you are on a page that has search capability and offers that option for you to directly search with the page engine from the address bar. Use this option at least 2 times and Firefox will suggest adding the search engine to your Firefox.

Contextual Search Engine Options: Use a Contextual Search mode option at least 2 times and Firefox will suggest adding the search engine to your Firefox so that it’s always available to you.

Intuitive Search Keywords: You can access various address bar search modes with convenient and descriptive keywords (e.g. @bookmarks,@tabs,@history, @actions).
Firefox now identifies all links in PDFs and turns them into hyperlinks.
Support HEVC playback on Linux.
Now you can sign PDFs without leaving Firefox. Save your signatures to re-use later.