Looking at slapcat | grep 'uid:\|cn=admins\|mail' | grep -C5 admin --color, we can see among other things:
dn: cn=admins,ou=groups,dc=yunohost,dc=org
objectClass: mailGroup
mail: root
mail: admin
mail: admins
mail: webmaster
mail: postmaster
mail: abuse
Which I thought would be enough for all mails sent to admin@ (and other adresses) to be dispatched to members of the admin group, but looking at other similar entries, I see that in fact the full email adress should be specified (so eg admin@domain.tld instead of just admin)
It’s a bit annoying because that makes that config bit dependent on the domain instead of catching all admin@* mails. I’m wondering if maybe we should switch to an alias regex somewhere in postfix’s conf instead …