The default Admin/Moderator/Staff groups have Delete button enabled and visible. As far as I know Discourse didn’t allow for deleting these groups. Potentially a bug?
I haven’t dared to click the delete button because I don’t want to screw up the functionality. The delete button is also visible on trust level groups.
Glad to see we display a clear message when you try deleting. I wonder though if removing the button will cause its own confusion. “Why do some groups not have the delete button?”
I’m not opposed to hiding the button, but would we want to instead grey it out like we do the delete button on the category edit page? Or include text noting that automatic groups can’t be deleted?