The golang.org/x/... repositories are part of the Go Project but outside the main Go tree.
They are developed under looser compatibility requirements than the Go core. In general, they will support the previous two releases and tip.
These repositories should have no third-party dependencies apart from other golang.org/x/... repositories. The only exceptions are golang.org/x/tools/gopls, golang.org/x/vscode-go, and golang.org/x/pkgsite. If you would like to add a new dependency to an x repository, please file an issue and cc @rsc and @andybons.
Install them with “go get”.
[docs] [source] golang.org/x/tools — godoc, vet, cover, and other tools.
[docs] [source] golang.org/x/mobile — libraries and build tools for Go on Android.
[docs] [source] golang.org/x/crypto — additional cryptography packages.
[docs] [source] golang.org/x/image — additional imaging packages.
[docs] [source] golang.org/x/net — additional networking packages.
[docs] [source] golang.org/x/sys — for low-level interactions with the operating system.
[docs] [source] golang.org/x/text — packages for working with text.
[docs] [source] golang.org/x/blog — the content and server program for blog.golang.org.
[docs] [source] golang.org/x/review — tools for code review.
[docs] [source] golang.org/x/exp — experimental code (handle with care).