Allow whitelisting of addresses
In mailman 2 it was possible to whitelist addresses so that they could post to a list without being subscribed, and the moderation interface provided the option to whitelist an address when letting a post through.
There doesn't seem to be any equivalent in mailman 3 as far as I can see - not only does the moderation interface not offer to do it but I can't find any sign of such a whitelist anywhere in the settings.
Not sure if this is just a deficiency in the postorious interface, or if the actual mailman backend doesn't support it.