In Telegram update 7.1 Anonymous Administrators have been introduced: their messages will appear with the group name instead of their account name.
Group Help considers them as administrators of the group (so it will respond to base commands), but to determine their effective powers for actions (e.g if they can ban or delete messages) it uses this logic:
• Anonymous administrators who have a unique custom title in the group will be able to use the powers that have actually been assigned to them
• For all other anonymous administrators the powers will be those set by the founder in the menu:
Settings ➜ Others ➜ Permissions ➜ Anonymous admins
👥 Anonymous Administrators will not appear on
/staff
⚙️ In any case, the settings will be modifiable only by those who have the real permissions to do so.