While tablet UI is still likely a ways away for the browser, it appears Mozilla has at least been working on it. Before we go any further, let’s first explain the confusion surrounding the issue.

A GitHub entry from nearly half a decade ago talks about the missing desktop like tab bar option, so it's clear that Android tablet users have requested this feature for quite a while.

Mozilla responded to a review mentioning the lack of tablet UI optimization for Firefox on Android. Mozilla confirmed that its team is not working on optimizing the tablet experience at the moment ...

The development of a new tablet interface with a PC-like tab bar in Firefox for Android marks an important milestone in Mozilla’s efforts to refine and innovate its mobile browser offering.