It seems they took a cue from Arc for the pinned tabs icons. Now they only need to add tab groups a la Tab Stash, Sideberry or Tree Style Tab, and combine that

It seems they took a cue from Arc for the pinned tabs icons. Now they only need to add tab groups a la Tab Stash, Sideberry or Tree Style Tab, and combine that with Sync. Still a lot of work ahead, but this looks very promising. Kudos to the Firefox team.