I noticed that, while apps seem very light by themselves, their use causes a rapid buildup of data associated with the Firefox application itself; I am talking in the order of megabytes in mere minutes. It seems a widespread problem rather than due to a specific app's beaviour; and it seems to happen even with apps which should't download nor produce noticeable amounts of data, like the stopwatch. Is it a bug in Firefox itself?

Can I do anything about it? The only way out seems to be deleting all Firefox data from Android; as even deleting all data from within Firefox settings does nothing. I can't see a setting section controlling apps, is there one?