$ git clone -n https://src.fedoraproject.org/rpms/dkms.git /var/lib/mock/f39-build-1531584-36214/root/chroot_tmpdir/scmroot/dkms
Cloning into '/var/lib/mock/f39-build-1531584-36214/root/chroot_tmpdir/scmroot/dkms'...
$ git fetch origin 6f40bc75ab72dae2cdc3dd29903e3719b5421a65:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dkms
 * [new ref]         6f40bc75ab72dae2cdc3dd29903e3719b5421a65 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6f40bc7 Adjust installation