$ git clone -n https://src.fedoraproject.org/rpms/libvpx8.git /var/lib/mock/f41-build-1021867-18041/root/chroot_tmpdir/scmroot/libvpx8
Cloning into '/var/lib/mock/f41-build-1021867-18041/root/chroot_tmpdir/scmroot/libvpx8'...
$ git fetch origin 5055cdb91ec95e12e3a662b14d898c3adf43639f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libvpx8
 * [new ref]         5055cdb91ec95e12e3a662b14d898c3adf43639f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5055cdb Retire old compat package in F41+