[0xbadcafebee]

Sometimes the hierarchy can be used without directly/perfectly extending the code. For example, in the CPAN world, you might publish your own module as "x/crypto/ssh/knownhosts/client". You don't even have to use the "x/crypto/ssh/knownhosts" code at all, it just looks like a similar namespace. (IIRC, CPAN requires a human in the loop who's moderating what new packages are listed; none of the craziness of PyPI where any insane person can release thousands of typosquatting malware modules)

You would hope a new module would reuse as much previous base modules as they can, but sometimes it's enough to just put some new code in that namespace, with the intent then that someone will find it easier, and build off of it. The hierarchy is for organization, discovery and distribution, as much as it is about good software development practice. The goal being to improve the overall software development ecosystem.

[evanelias]

For critical security-related code, I'd argue that's not a good property at all for module namespacing! Quite the opposite. Even with a human in the loop.

(and I was a professional Perl programmer for the first 5 years of my career, so I'm not asserting this out of lack of familiarity with CPAN!)

That all said: I don't even think what you're saying about CPAN is terribly similar to the situation being discussed here, since Go's x/crypto/ssh (and all other x/ packages) are officially part of the Go Project and are maintained by the Go core maintainers. See https://pkg.go.dev/golang.org/x. Third-party Go developers cannot add new packages to this namespace at all.