Translations:Help:Extension:Translate/Unstructured element translation/9/en

The message group id,  , must be unique, so don't reuse the same id for multiple groups. The second parameter to the  , refers to the  Mediawiki:Sidebar-messages  page. The label is shown in dropdowns and other places where you can select a message group. The description is shown in Special:Translate. Those are the values you can and should change to what suits your wiki when adding a new custom message group.