$ go help get
usage: go get [-d] [-fix] [-t] [-u] [build flags] [packages]
...
Get also accepts all the flags in the 'go build' and 'go install' commands,
to control the installation. See 'go help build'.
...

get does not accept -o 'go build' flag. 'go install' docs are more precise in this
regard, they refer to 'build flags' which do not include -o.

Moreover, 'go install' does not have own flags, so reference to 'go install' flags looks
confusing ('go install' merely redirects to 'go build' for flags description).

I think 'go help get' must say something along the lines of:

Get also accepts build flags to control the build. See 'go help build'.