There is a question I think the community of unix.SE would be able to provide an answer to, and which is related to the Simple Mail Transfer Protocol and seeks information about some historic background (i.e. "what was the technical background/reason that caused tha 7bit encoding limitation")
Even though I have seen both tags
history used for questions that related to the question I feel unsure if this is an permitted on topic question.
I expect the question to be answerable with reference to some limitations with regards to stop characters and transmission channels used during the time SMTP was used. With that respect the question would imho not be opinion based, but might have some factual background, I am simply not aware of and could not find adequate information yet, hence the desire to ask it.
It would be great also, to receive an information if there is a different SE community that would be more related to the question. Yet I think that a big percentag of MTA systems are rooted in the unix/linux world.