$ git clone -n https://src.fedoraproject.org/rpms/ghc-x509-system.git /var/lib/mock/f40-build-744514-111739/root/chroot_tmpdir/scmroot/ghc-x509-system
Cloning into '/var/lib/mock/f40-build-744514-111739/root/chroot_tmpdir/scmroot/ghc-x509-system'...
$ git fetch origin 4b6fcf3c64576e87f359004e4bdcecfb727575f1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-x509-system
 * [new ref]         4b6fcf3c64576e87f359004e4bdcecfb727575f1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4b6fcf3 bump release