Every permission are for operators by default. If a player doesn't have the permission for that command, he cannot use it (help page doesn't show commands that the player doesn't have the permission to use).
So, removing a permission will remove that command/feature, this is a way to remove/disable OreAnnouncerGUI features.
You can give all permissions with
Every permission is listed below:
|oreannouncergui.admin.edit.blocks||Allow access to /oa blocks|