This is related to but different from {T71445}. That is about the MW namespace.
There are many pages in project space like https://en.wikipedia.org/wiki/Wikipedia:WikiProject_User_scripts/Scripts/CloseAFD.js . People can import these, but they don't run for every user and are not available in preferences.
These are imported directly, so should not be editable by everyone who can edit articles. This problem was recognized [long ago](https://en.wikipedia.org/w/index.php?title=Special:Log&type=protect&page=Wikipedia%3AWikiProject+User+scripts%2FScripts%2FCloseAFD.js), and people have been protecting them manually.
However, there is a case to make these editable by a wider group than those who edit MediaWiki:Common.js.
My proposal is:
JS pages outside of MediaWiki namespace should be editable (only) by anyone who can edit/merge MediaWiki: namespace JS, plus:
* For User space, that particular user (User:Somebody/something.js can be edited by Somebody as well).
* For other pages (not in User space), those in a jscurator group.
If you're not in jscurator and want to modify such a script, you can copy it to your user space, then do a {{requested edit}} (or suggest it on talk).
A alternate approach is to drop jscurator, and only let the people (typically local admins, local interface editors, and global interface editors) trusted to edit MediaWiki:Common.js edit shared pages like CloseAFD.js.