$ git clone -n https://src.fedoraproject.org/rpms/golang-github-sgreben-flagvar.git /var/lib/mock/f41-build-1036366-18724/root/chroot_tmpdir/scmroot/golang-github-sgreben-flagvar
Cloning into '/var/lib/mock/f41-build-1036366-18724/root/chroot_tmpdir/scmroot/golang-github-sgreben-flagvar'...
$ git fetch origin 8b327181e015ae80efc3719becfd90a2f6ee6192:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-sgreben-flagvar
 * [new ref]         8b327181e015ae80efc3719becfd90a2f6ee6192 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8b32718 Fix FTBFS