Firefox Beta and Developer Edition
Release Notes

You can now use the context menu on toolbar buttons added by add-ons to remove the add-on

WebRender enabled by default for Desktop NVIDIA GPUs on Windows 10

Enterprise policy support for MacOS

You can now select multiple tabs from the tab bar, and mute, move, bookmark, or pin them quickly and easily

TLS certificates issued by Symantec are no longer trusted by Firefox. Website operators are strongly encouraged to replace any remaining Symantec TLS certificates as soon as possible, before Firefox 64 final release on December 11.

Changes to URL bar autocomplete shortcuts: use ctrl-enter to canonicalize a word to a .com URL. On MacOS, cmd-enter now opens in a tab.

about:crashes has been redesigned to make it clear when a crash is being submitted to Mozilla, as well as being clear that removing crashes locally does not remove them from crash-stats.mozilla.com

Support for RSS preview and live bookmarks is being removed