[Evolution] What is M-client

[Leonard Evens <len math northwestern edu>]

I have recently set up evolution on my home machine to use different
incoming and outgoing mail servers.   It behaves differently in some
ways than it did with my previous setup, and I am trying to understand
just why.

It used to be that when I clicked on Send/Receive for my inbox, after a
very short pause, I got a listing of my incoming mail.
Now it says it is applying filters.  It does it pretty quickly, but I
don't know why it is doing that and what is accomplished.  

If I click on the Edit menu, there is a Message Filters option which
brings up a box showing me a list of either incoming or outgoing Message
Filters.  the latter is an empty list, and the former has one item
checked M-client.

Is this what is being applied?   What does it do?
-- 
Leonard Evens len math northwestern edu
Professor Emeritus, Department of Mathematics, Northwestern University