https://translations.launchpad.net/mailman/3.0/+pots/mailman/ru/+details Is this is translation for use with mailman? Or what is it for?
That's for Mailman, but it's for version 3.0. I have no idea how useful it would be with Mailman 3 HEAD (soon to be released as Mailman 3.2). Probably the majority of messages are the same, so it should be pretty useful.