Where is the #Fediverse " #handle" syntax, @name@example.com, formally defined? I don't see it in the W3C #ActivityPub spec, nor in #RFC7565, the #Webfinger 'acct' URI scheme spec. Is it a #Mastodon convention which became universal? I am writing software to study handles, and I would rather base it on a spec than a social convention.

Where is the #Fediverse " #handle" syntax, @name@example.com, formally defined? I don't see it in the W3C #ActivityPub spec, nor in #RFC7565, the #Webfinger 'acct' URI scheme spec. Is it a #Mastodon convention which became universal? I am writing software to study handles, and I would rather base it on a spec than a social convention.