Comment 76 for bug 861664

They are not visible in the addons manager. I've reinstalled most of them in the meantime because I needed them, but they were present in the addons.sqlite file. For those that I didn't reinstall yet, they are not listed under "Extensions" on "about:support". They have also been removed from the extensions subdir of the profile, as a cursory look indicates, but are (were?) still present in addons.sqlite.