Response file (@file) parsing is now supported for the compile, link, asm, cgo, cover, and pack tools. The response file contains whitespace-separated arguments with support for single-quoted and double-quoted strings, escape sequences, and backslash-newline line continuation. The format is compatible with GCC's response file implementation to ensure interoperability with existing build systems.
go test now invokes the stdversion vet check by default. This reports the use of standard library symbols that are too new for the Go version in force in the referring file, as determined by go directive in go.mod and build tags on the file.
The go command no longer has support for the bzr version control system. It will no longer be able to directly fetch modules hosted on bzr servers.
go tool trace's -http argument now restricts the listen address to localhost when passed only a port (e.g., -http=:6060). This change makes go tool trace consistent with the behavior of go tool pprof's -http flag. To listen on all addresses, explicitly include the specified address (e.g., -http=0.0.0.0:6060).