$ git clone -n https://src.fedoraproject.org/rpms/ca-certificates.git /var/lib/mock/f42-build-side-1-3498989-45963/root/chroot_tmpdir/scmroot/ca-certificates
Cloning into '/var/lib/mock/f42-build-side-1-3498989-45963/root/chroot_tmpdir/scmroot/ca-certificates'...
$ git fetch origin 5a91943b49769dd234212d46e15a81e055ed27b0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ca-certificates
 * [new ref]         5a91943b49769dd234212d46e15a81e055ed27b0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5a91943 Revert dropping of /etc/pki/tls/certs/ca-bundle.trust.crt