[Evolution] How does the evo filter for mailing list work?

[Mikhail Ramendik <mr ramendik ru>]

Hello!

I have viewed full headers of messages in one of the mailing lists I am
subscribed to, and found no List-* or Mailing-List kludge. And yet Evo
has successfully created a filter for this mailing list, and this filter
works!

Question: HOW does it work? By Reply-To?

I need it for development of something very different (a server-side
filter). 

Thanks in advance for any explanation!

Yours, Mikhail Ramendik