$ git clone -n https://src.fedoraproject.org/rpms/flow-tools.git /var/lib/mock/f45-build-9082-398/root/chroot_tmpdir/scmroot/flow-tools
Cloning into '/var/lib/mock/f45-build-9082-398/root/chroot_tmpdir/scmroot/flow-tools'...
$ git fetch origin 63d8a6b3e89093058f36d190b3c7a27b5489962e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/flow-tools
 * [new ref]         63d8a6b3e89093058f36d190b3c7a27b5489962e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 63d8a6b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild