$ git clone -n https://src.fedoraproject.org/rpms/python-mutagen.git /var/lib/mock/f40-build-2222826-52712/root/chroot_tmpdir/scmroot/python-mutagen
Cloning into '/var/lib/mock/f40-build-2222826-52712/root/chroot_tmpdir/scmroot/python-mutagen'...
$ git fetch origin 917b52f732adb848353dc71d6c88725334f0e166:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-mutagen
 * [new ref]         917b52f732adb848353dc71d6c88725334f0e166 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 917b52f New upstream