Yeah these are now handled by the admins group behind the scene … though so far there’s no way to explicitly see them from the webadmin … but oneday™ we’ll implement mail-alias management for groups, which should also solve a bunch of use case and have a minimalist mailing-list mechanism (eg behind able to define contact@).
It’s actually not that complex to implement, cf Use the group mechanism as mailing distribution list · Issue #1537 · YunoHost/issues · GitHub