Preference folders standardized in all projects

Balaco <[email protected]> Mon, 13 Nov 2017 00:30:06 -0200
Newsgroups gmane.comp.mozilla.wishlist
Message-ID <[email protected]>
Right now, I found out that Thunderbird preference folder is

~/.thunderbird

But Firefox preference folder is

~/.mozilla/firefox

Why those are different? Either all projects have their own folder, or 
they share a parent folder with all Mozilla project.

Why it is like that?