Yes, golang.org/x/ is of a "nursery" of sorts for things that are stdlib-ish but not fully baked enough that the maintainers want to support it under the 1.0 compatibility promise [0]

https://golang.org/pkg/#subrepo

> These packages are part of the Go Project but outside the main Go tree. They are developed under looser compatibility requirements than the Go core.

0: https://golang.org/doc/go1compat