Welcome to Firefox for Android Add-ons.
Add extra features and styles to make Firefox for Android your own.
CloseReview for Folder Categories by phubert
Rated 1 out of 5 stars
SHOWS no categories TO assign
And, if, as other comments say, nothing can be DONE with "categories", then it has no purpose in the first place
To create your own collections, you must have a Mozilla Add-ons account.