$ git clone -n https://src.fedoraproject.org/rpms/magic.git /var/lib/mock/f40-build-754313-117634/root/chroot_tmpdir/scmroot/magic
Cloning into '/var/lib/mock/f40-build-754313-117634/root/chroot_tmpdir/scmroot/magic'...
$ git fetch origin d21e768371314f720759eed029bcee10e2264fa0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/magic
 * [new ref]         d21e768371314f720759eed029bcee10e2264fa0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d21e768 8.3.451