Version 69.0a1, first offered to Nightly channel users on May 20, 2019
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 Twitter account as well as read our Nightly Blog.
Firefox will give Windows hints to appropriately set content process priority levels, meaning more processor time spent on the tasks you're actively working on, and less processor time spent on things in the background (with the exception of video and audio playback).
Users who use userChrome.css or userContent.css files to customize Firefox may need to flip the toolkit.legacyUserProfileCustomizations.stylesheets pref to true in order for Firefox to load these files. This is to avoid touching the disk unnecessarily during start-up for users that don't have those files. This pref will have been set automatically for users on Firefox 68 who had either userChrome.css or userContent.css already exiting in their profile directories.