$ git clone -n https://src.fedoraproject.org/rpms/gn.git /var/lib/mock/f41-build-850203-165163/root/chroot_tmpdir/scmroot/gn
Cloning into '/var/lib/mock/f41-build-850203-165163/root/chroot_tmpdir/scmroot/gn'...
$ git fetch origin a83342dc49e4a8acfd1b74856fb1f6ea1f25c2a3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gn
 * [new ref]         a83342dc49e4a8acfd1b74856fb1f6ea1f25c2a3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a83342d Update to version 2190