$ git clone -n https://src.fedoraproject.org/rpms/rust-matrixcompare-mock.git /var/lib/mock/f42-build-side-1-3588715-46949/root/chroot_tmpdir/scmroot/rust-matrixcompare-mock
Cloning into '/var/lib/mock/f42-build-side-1-3588715-46949/root/chroot_tmpdir/scmroot/rust-matrixcompare-mock'...
$ git fetch origin 8ce42d55d18b41a677fe09ff230e3a3711cc60c4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-matrixcompare-mock
 * [new ref]         8ce42d55d18b41a677fe09ff230e3a3711cc60c4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8ce42d5 Update num dependency to 0.4