Mobile tab grouping

[droidcraft]

With the ability to move tabs currently in nightly it would also be nice to be able to group tabs the same way chrome does.

[T77]

How had this feature taken over 4 years. 

I switched to Firefox and was honestly shocked it wasn't a feature already

[ray8]

Having this feature on mobile would be huge. I assume we're talking regular tab groups like on desktop or Chrome Mobile, not the Collections feature. It's a big part of how I use a browser, and it's the only reason I've hesitated to switch my mobile browser from Chrome for so long. If this was added, I'd abandon Chrome in a heartbeat and never look back.