$ git clone -n https://src.fedoraproject.org/rpms/golang-github-mattn-runewidth.git /var/lib/mock/f39-build-1503975-34997/root/chroot_tmpdir/scmroot/golang-github-mattn-runewidth
Cloning into '/var/lib/mock/f39-build-1503975-34997/root/chroot_tmpdir/scmroot/golang-github-mattn-runewidth'...
$ git fetch origin 8fa480f0e11beae1508adcf279eb0e9e5004acd1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-mattn-runewidth
 * [new ref]         8fa480f0e11beae1508adcf279eb0e9e5004acd1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8fa480f Update to 0.0.15 - Closes rhbz#2224923