Interface administrators can edit CSS and JS pages that they do not own (that is, any page ending with
.js that is either in the
MediaWiki: namespace or is another user's user subpage). In particular, they have the ability to edit sitewide CSS/JS pages (pages such as MediaWiki:Common.js or MediaWiki:Vector.css, or the gadget pages listed on Special:Gadgets). These pages are executed by the browser of wiki editors and readers as code, which can be used to change how content is styled, change the behavior of pages, or even create highly complex tools. In addition, they can also edit all other pages in the MediaWiki namespace.
Editing CSS/JS that gets executed in other users' browsers is very powerful and potentially dangerous in the hands of a malicious user. Interface administrators should be users who need it, who are trusted by the community, and who follow common basic password and computer security practices (use strong passwords, do not reuse passwords, use two-factor authentication if possible, do not install software of questionable origin on your machine, use antivirus software if that's a standard thing in your environment).
Administrators and interface administrators can edit pages that are not CSS nor JS in the MediaWiki namespace. (e.g. MediaWiki:Sidebar)
You can learn more about the motivation behind this user group here.
Apply to become an Interface administrator
Every administrator who can make plausible a need to edit the interface will be granted temporary or permanent interface administrators right on request at the Bureaucrats' noticeboard per bureaucrats discretion.
If administrator status is revoked as result of inactivity or result of a deadmin request, interface admin rights shall also be removed.
If administrator status is voluntarily relinquished, interface admin rights may be retained if needed.
Non-administrator users may request interface administrators right via Commons:Administrators/Requests. The same criteria as for normal admin requests apply.
Non-administrator users who hold interface administrators right are subject to Commons:Administrators/De-adminship in the same way administrators are.