Hi Erik, thank you very much for this work.
I noticed small difference in capitalization of mailing list name:
Compare:
https://mailman.common-lisp.net/pipermail/cl-plus-ssl-devel/2014-April/000000.html
https://mailman-test.common-lisp.net/pipermail/cl-plus-ssl-devel/2014-April/000249.html
Your new mailman-test archive does better job whey it says
"More information about the cl-plus-ssl-devel mailing list", while current version says
"More information about the Cl-plus-ssl-devel mailing list" - capitalized list name.
Interesting, that both versions use capitalized list name
in another phrase: "Previous message: [Cl-plus-ssl-devel]..."
If we check some elder messages, for example
https://mailman-test.common-lisp.net/pipermail/cl-plus-ssl-devel/2014-January/000248.html
the list name is lower case everywhere.
I don't see other problems (although I don't have
good ideas how to verify the archive).