>> 2369 The Use of URLs as Meta-Syntax for Core Mail List Commands and their
>> Transport through Message Header Fields. [snip]
>+1. Every mailing list run by everyone everywhere should support
>RFC 2369, RFC 2919, and RFC 2142 standards. It's trivially easy and
>there are precisely zero valid excuses for not doing it.
There are some issues with helpful spam filters that fetch the URLs in
list-unsubscribe headers to see if they lead somewhere malicious, but
they're not all that hard to deal with.
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