$ git clone -n https://src.fedoraproject.org/rpms/nv-codec-headers.git /var/lib/mock/f42-build-side-1-3499051-45964/root/chroot_tmpdir/scmroot/nv-codec-headers
Cloning into '/var/lib/mock/f42-build-side-1-3499051-45964/root/chroot_tmpdir/scmroot/nv-codec-headers'...
$ git fetch origin dc5190a459302206e878fdf37ddcb54b09c39db4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nv-codec-headers
 * [new ref]         dc5190a459302206e878fdf37ddcb54b09c39db4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc5190a Update to 13.0.19.0