I don't control python-dev, so that's up those admins.
I could add it, but I would have to reconstruct the footer for Mailman 3 as the current ones are on-disk and not exposed to the UI, so I have to basically override what's currently there. If someone wants to propose a new footer then they can email me or start a new thread and hash one out. The allowed variables are:
$hyperkitty_url: Permalink to archived message in Hyperkitty
$listname: Name of the Mailing List e.g.
ant@example.com $list_id: The List-ID header e.g.
ant.example.com $display_name: Display name of the mailing list e.g. Ant
$short_listname: Local part of the listname e.g. ant
$domain: The domain part of the listname e.g.
example.com $info: The mailing list's longer descriptive text
$request_email: The email address for -request address
$owner_email: The email address for -owner address
$site_email: The email address to reach the owners of the site
$language: The two letter language code for list's preferred language e.g. fr, en, de