I'd like to suggest to move the "User Scripts" tab in the Add-ons Manager
below the Plugins tab:
Τhe GM's "User Scripts" tab is something extra to the Firefox interface,
so I think it's better to appear below the default ones.
But now it is correctly position:
Greasemonkey is an extension.
Any other opinions?
That wasn't an accidental change; it's intentionally next to Extensions because User Scripts are essentially extensions.
I also prefer to see it below "Plugins" as those are from FF itself. Actually, from FF 18 it should then be below "Dictionaries".
I prefer below "Plugins" too.
And Stylish also place below "Plugins" with label "User Styles". Greasemonkey Place next to it look better.