Hi,
I need to make a user role, that only has access to appearance.
Is there someone out there, who allready has this.
From the code, the Appearance section of the site administration should be available (beside the site administrators) to users with the capability "moodle/my:configsyspages" or "moodle/tag:manage". Just note that the administration UI does not allow to directly modify the mustache templates. I am not sure what are your exact expectations on such "template only user" role.