$ git clone -n https://src.fedoraproject.org/rpms/magic.git /var/lib/mock/f39-build-1466094-33646/root/chroot_tmpdir/scmroot/magic
Cloning into '/var/lib/mock/f39-build-1466094-33646/root/chroot_tmpdir/scmroot/magic'...
$ git fetch origin 757b16318dde8ade406b320f67ea5523d9460e8d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/magic
 * [new ref]         757b16318dde8ade406b320f67ea5523d9460e8d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 757b163 8.3.439