$ git clone -n https://src.fedoraproject.org/rpms/magic.git /var/lib/mock/f45-build-17918-505/root/chroot_tmpdir/scmroot/magic
Cloning into '/var/lib/mock/f45-build-17918-505/root/chroot_tmpdir/scmroot/magic'...
$ git fetch origin 9920c13e9dc151e73724e7edf1a577d1ce1753ca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/magic
 * [new ref]         9920c13e9dc151e73724e7edf1a577d1ce1753ca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9920c13 8.3.682