Since people keep asking:
This is on the latest version, and I'm on Windows.
They got rid of this on some platforms/configurations, but it still exists for others.
I think specifically this is happening because I'm making the mistake of trying to use Firefox's multiple profile support
about:profiles even though they are profiles, will make folders in the profiles folder, and are usable via --profile. by all means, they’re profiles, they just don’t get written to ~/.mozilla/firefox/profiles.ini@_r Ooh, interesting! I note the opposite is true as well: profiles created through the old UI don't show up in the new list.
I wonder if you can "upgrade" by using the "Copy Profile" option in the new UI while in an "old style" non-default profile...
@_r Oh wow, apparently the list of new-style profiles is stored... inside your profile!
*insert "Yo Dawg" meme here*
@imsop what the fuck. what idiot came up with this?
is it… the main profile? or is it duplicated in every profile?
@_r Ah, I may have spoken too soon; they're *tied to* a primary profile, but not actually *inside* it.
There's a new "Profile Groups" folder, which is a bunch of SQLite DBs, because text files are sooo last century. Looks like a "StoreID" key in profiles.ini is used to bootstrap from the old system to the new one. So migrating might require a little more hacking.