$ git clone -n https://src.fedoraproject.org/rpms/desktop-file-utils.git /var/lib/mock/f42-build-side-1-3501730-45976/root/chroot_tmpdir/scmroot/desktop-file-utils
Cloning into '/var/lib/mock/f42-build-side-1-3501730-45976/root/chroot_tmpdir/scmroot/desktop-file-utils'...
$ git fetch origin b08516ebbce0c577669cb455e2906f9cfc038ea1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/desktop-file-utils
 * [new ref]         b08516ebbce0c577669cb455e2906f9cfc038ea1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b08516e 0.28 update