$ git clone -n https://src.fedoraproject.org/rpms/guidelines-support-library.git /var/lib/mock/f42-build-side-1-3498269-45962/root/chroot_tmpdir/scmroot/guidelines-support-library
Cloning into '/var/lib/mock/f42-build-side-1-3498269-45962/root/chroot_tmpdir/scmroot/guidelines-support-library'...
$ git fetch origin f818ed665c9b595aa7f482aadabc83f7b82a9939:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/guidelines-support-library
 * [new ref]         f818ed665c9b595aa7f482aadabc83f7b82a9939 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f818ed6 Disabled 32-bit build.