As the user rights system is set up right now, it is technically impossible to allow a user group to edit the interface texts without allowing them to edit the standard scripts (.js and .css pages). Given the fact that the risks behind these different actions is on a totally different level (abuse of the rights to edit texts may harm the site's reputation, but not the privacy of its users)), it should be technically possible to allow the former without the latter.

See also:

• T165981: Implement a prototype JavaScript review system for MediaWiki
• T71445: Implement a proper code-review process for MediaWiki JS/CSS pages on Wikimedia sites
• mw:Extension:Gadgets/Gadgets 2.0#Features