These two lines should not be in CheckUser.php:

$wgGroupPermissions['checkuser']['checkuser'] = true;
$wgGroupPermissions['checkuser']['checkuser-log'] = true;

I give CheckUser to my sysops and don't use a dedicated group for it. Having to undo these group assignments is not the best way to go, so just remove those lines and ask people to install it this way in LocalSettings.php:

require_once ( "$IP/extensions/CheckUser/CheckUser.php" );
$wgGroupPermissions['checkuser']['checkuser'] = true;
$wgGroupPermissions['checkuser']['checkuser-log'] = true;

And then of course we can choose to assign the permissions to whatever group without having to undo the assignments made in CheckUser.php.

Version: master
Severity: trivial