“With software there are only two possibilities: either the users control the program or the program controls the users. If the program controls the users, and the developer controls the program, then the program is an instrument of unjust power.”

- Richard M. Stallman

Your distro can also decide what version to be on for each package. Slackware regularly rolls back a broken package until upstream fixes it.

Even if it’s a completely valid address and the domain exists, they still might’ve fat fingered the username part. Going to extreme lengths to validate email addresses is pointless, you still have to send an email to it anyway.

Don’t be ridiculous, I’m going to use an open source password manager to fill an IPv6 address for my email server into the DoorDash signin page.