All buildfarm mailing lists are maintained at the PostgreSQL Mailing Lists site,

All buildfarm owners, and anybody else who is interested, should be subscribed to the buildfarm-members mailing list. This is a very low volume list, but it's the place to discuss problems, and also where new releases get announced.

There are also two lists that provide notification of status.

Buildfarm owners who just want email notifications of status of their own animals don't need to subscribe to the status lists. This can be configured in the mail_events section of the animal's config file.