Hi Firefox team.
I do not have question, but have some comment.
I expect when you uninstall FF it should keep the content of "Downloads" which may have some valuable stuff, which has nothing to do with FF itself.
But I would expect the crap "extensions" like "PriceGong" should be deleted!
And I would put clear comments in help how to remove that carp, which usually forcefully installed.
When you uninstall Firefox you have the option to keep your personal data (located in your profile folder) or to delete it. If you don't delete it, things like the list of downloaded files should still be there if you reinstall Firefox.