This might be a bug in addtag, but I'm not even sure what this subcommand is useful for. It seems to try to assign the minimum compatible tag in the file name, but from my limited testing it always ends up with the linux_x86_64 tag, which isn't useful. So if you pass a wheel which only has a linux_x86_64 tag, it does nothing, and for wheels which have manylinux tags it also adds linux_x86_64, which isn't very useful either. I wonder if this is a regression, as there aren't any real tests for this functionality...
Originally posted by @lkollar in #439 (comment)