I've been auditing the space hogs on my device, and despite Firefox being a moderate size app, the USER DATA has ballooned to half a GB. This is despite me only syncing bookmarks and passwords, not site history and other stuff. So now I'm unsure if it's okay to delete this. I'm pretty sure that a chunk of this data could just be held in cache rather than user data.
Could you add a feature to select the data held between sessions?