$ git clone -n https://src.fedoraproject.org/rpms/golang-modernc-cc-4.git /var/lib/mock/f40-build-2240373-53632/root/chroot_tmpdir/scmroot/golang-modernc-cc-4
Cloning into '/var/lib/mock/f40-build-2240373-53632/root/chroot_tmpdir/scmroot/golang-modernc-cc-4'...
$ git fetch origin 9486c39e327f7b8c11a644cdf26c934ee0e63c59:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-modernc-cc-4
 * [new ref]         9486c39e327f7b8c11a644cdf26c934ee0e63c59 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9486c39 Update to 4.18.0