netrcauth uses a .netrc file (or _netrc file on Windows) to implement the GOAUTH protocol described in https://golang.org/issue/26232. It expects the location of the file as the first command-line argument.
Example GOAUTH usage:
export GOAUTH="netrcauth $HOME/.netrc"
See https://www.gnu.org/software/inetutils/manual/html_node/The-_002enetrc-file.html or run 'man 5 netrc' for a description of the .netrc file format.