$ git clone -n https://src.fedoraproject.org/rpms/dnf.git /var/lib/mock/f40-build-2686650-68067/root/chroot_tmpdir/scmroot/dnf
Cloning into '/var/lib/mock/f40-build-2686650-68067/root/chroot_tmpdir/scmroot/dnf'...
$ git fetch origin 1b9a019cc13dcdeec6a3e38d62ac271b0486ca54:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dnf
 * [new ref]         1b9a019cc13dcdeec6a3e38d62ac271b0486ca54 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1b9a019 Update to 4.19.2