That does this RFC even say? I read it twice and it seems to say "Some mail servers may use the part of an email after any character as a subaddress which doesn

That does this RFC even say? I read it twice and it seems to say "Some mail servers may use the part of an email after any character as a subaddress which doesn't affect which inbox a message is delivered to." It seems to only talk about the receiving server and gives no way for the sending server to do anything useful as it doesn't specify the character to use if the receiver implements it at all. I think this is good, I would like to not have senders try to guess anything about the structure of my email, but it makes me wonder what the point of having the RFC at all is.