$ git clone -n https://src.fedoraproject.org/rpms/pcem.git /var/lib/mock/f40-build-805079-144688/root/chroot_tmpdir/scmroot/pcem
Cloning into '/var/lib/mock/f40-build-805079-144688/root/chroot_tmpdir/scmroot/pcem'...
$ git fetch origin b9781bc6c8bc8c012e75dc8710d544454bd59283:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pcem
 * [new ref]         b9781bc6c8bc8c012e75dc8710d544454bd59283 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b9781bc Drop i686 builds