$ git clone -n https://src.fedoraproject.org/rpms/rubygem-ansi.git /var/lib/mock/f45-build-34782-691/root/chroot_tmpdir/scmroot/rubygem-ansi
Cloning into '/var/lib/mock/f45-build-34782-691/root/chroot_tmpdir/scmroot/rubygem-ansi'...
$ git fetch origin 56a784cc825ed47c3beaf7f2530d01efd03b7c03:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-ansi
 * [new ref]         56a784cc825ed47c3beaf7f2530d01efd03b7c03 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 56a784c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild