For our internal communication channel, my understanding is that we can request
a list on the main Debian list server. That list could for example be called
debian-octave@lists.debian.org. We could extend the scope of the list by
welcoming users that want to discuss issues related to Octave in Debian, and
also upstream developers (at least jwe and JordiGH are already subscribed to
pkg-octave-devel@). The procedure for requesting such a list is described
there:
https://www.debian.org/MailingLists/HOWTO_start_list
We should not wait for too long before requesting it, since Alioth mailing
lists will be disabled in the beginning of February.