デスクトップ版Firefox Nightly、新UI『Proton』をデフォルトで有効化

あるAnonymous Coward 曰く、

Firefox/Proton — MozillaWiki
https://wiki.mozilla.org/Firefox/Proton

[meta] Proton — Firefox visual refresh
https://bugzilla.mozilla.org/show_bug.cgi?id=1678742

Enable Proton panels and context menus on Nightly by default
https://bugzilla.mozilla.org/show_bug.cgi?id=1703716

The new tab design is less compact and rather confusing due to missing vertical separators
https://www.reddit.com/r/firefox/comments/mmtex2/the_new_tab_design_is_less_compact_and_rather/