$ git clone -n https://src.fedoraproject.org/rpms/igt-gpu-tools.git /var/lib/mock/f38-build-side-42-init-devel-1298440-30684/root/chroot_tmpdir/scmroot/igt-gpu-tools
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1298440-30684/root/chroot_tmpdir/scmroot/igt-gpu-tools'...
$ git fetch origin d67251470e273e2144fe8da4ad89678cbb543ba3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/igt-gpu-tools
 * [new ref]         d67251470e273e2144fe8da4ad89678cbb543ba3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d672514 Don't forget to update sources