Unless it was recently added, groups are not a thing on Mastodon itself. I do know in the Mastodon side of things a lot of people use Guppe: a.gup.pe/ for groups, which work in the same fashion as Friendica groups, just with no moderator/admin.

In the case of the groups, all 3 have it in their description that they’re groups.

Because Mastodon has no support for groups there’s no indicator anywhere other than the description that an account is a group account.

@HistoPol@mastodon.social @jamie@boothcomputing.social @oliphant@oliphant.social @snarfed.org@snarfed.org @luca@sironi.tk @PCOWandre@jauntygoat.net @chronohart@tech.lgbt @snarfed@indieweb.social