Manual:$wgGroupPermissions

Details
$wgGroupPermissions is a two-dimensional array indexed by user group and available permissions. The value can be either to grant the permission or  if it should not be granted.

Those permissions, which are granted with $wgGroupPermissions, are always cumulative. If a user is member of different groups, then the user will get a right if it is granted to at least one of these groups even if it is not granted to their other groups. In other words, If one of the user's groups has a right, then it is not possible to take the right away using. Instead use  to revoke permissions.

Example
Since REL 1.25 do in :

This gives all registered users the ability to edit pages.

Custom user groups
You can also define your own user groups. User group names can be no longer than 255 characters. The groups, which have been defined either in or in , can be assigned to users through the wiki Special:Userrights interface.

Example (until REL 1.24 or in LocalSettings.php )

Example in  (since REL 1.25)

This creates a group called "trustworthy".

Now add human readable names for your newly created group to the wiki for the "trustworthy" group, e.g. on page "MediaWiki:Group-trustworthy" in plural "Trustworthy editors" and on page "MediaWiki:Group-trustworthy-member" in singular "Trustworthy editor". This is an optional but recommended step.

Users of that group have the same permissions as users from the groups "autoconfirmed" and "bot". Additionally, they will be able to delete and protect pages, and to patrol edits.

For in-depth documentation, see.

Default values
Default values vary from version to version. You may find the one which apply to your mediawiki setup in . For more info visit.

Use by extensions
Some extensions, such as or , add new rights which can be configured and assigned in the same manner.