$ git clone -n https://src.fedoraproject.org/rpms/magic.git /var/lib/mock/f41-build-side-1-2937744-35281/root/chroot_tmpdir/scmroot/magic
Cloning into '/var/lib/mock/f41-build-side-1-2937744-35281/root/chroot_tmpdir/scmroot/magic'...
$ git fetch origin 759b654b38c27caa6394cb8b518cb688bd9d5c0f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/magic
 * [new ref]         759b654b38c27caa6394cb8b518cb688bd9d5c0f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 759b654 8.3.497