This extension mocks a command line environment, it does not actually execute scripts from the command line. There may be unexpected results due to this fact. Use at your own risk. If you can, you should execute maintenance scripts from the command line instead. Please report any unexpected results on talk page.
Do not grant rights to the MaintenanceShell lightly. Maintenance scripts are powerful tools which can have a significant impact on your wiki. They are implemented as command line scripts instead of Special pages because they are irreversible and leave no trace.
This right (for security reasons not assigned to any group by default) grants the right to use Special:MaintenanceShell.
// Grant access to Special:MaintenanceShell to the "developer" user group:$wgGroupPermissions['developer']['maintenanceshell']=true;# Or
// Create a new "maintenanceshell" user group for Special:MaintenanceShell:$wgGroupPermissions['maintenanceshell']['maintenanceshell']=true;