You can disable the popup but still invoke the tool manually from the main menu. I reaffirm my previously expressed dissatisfaction with modern software "features" and add that there are plenty of defaults in Firefox that I personally dislike. That includes anything that pops up unsolicited without good reason.
From a UI perspective, auto tab groups are just an extra button as far as I can tell, so it's not clear why it's getting the axe from this site, just from a pure "this is annoying" point of view.
The flow is 1) you drag a tab over another tab and it suggests a name for the tab group and 2) you click on a tab group and another button offers to suggest more of your tabs you can add to the group. That's less intrusive than Firefox Translations are by default.
