$ git clone -n https://src.fedoraproject.org/rpms/libvpx.git /var/lib/mock/f40-build-1967870-25215/root/chroot_tmpdir/scmroot/libvpx
Cloning into '/var/lib/mock/f40-build-1967870-25215/root/chroot_tmpdir/scmroot/libvpx'...
$ git fetch origin f327457c7f55fbe111b7b813c6eb25f6928a276d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libvpx
 * [new ref]         f327457c7f55fbe111b7b813c6eb25f6928a276d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f327457 Update to 1.14.1