“You’ll notice softer tab shapes, a warmer color palette, updated icons, and after hearing from many of you, the return of Compact Mode and new theme options to make Firefox your own.”
Softer tabs and a warmer palette. Compact Mode returns, which is Mozilla admitting it should not have removed it. Firefox has been losing market share for a decade and the answer is round corners. The engine work that would actually matter does not get a blog post.