$ git clone -n https://src.fedoraproject.org/rpms/rubygem-bindex.git /var/lib/mock/f45-build-34792-691/root/chroot_tmpdir/scmroot/rubygem-bindex
Cloning into '/var/lib/mock/f45-build-34792-691/root/chroot_tmpdir/scmroot/rubygem-bindex'...
$ git fetch origin d249837480ccdffbd6526ae95cd08fe55a9928a5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-bindex
 * [new ref]         d249837480ccdffbd6526ae95cd08fe55a9928a5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d249837 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild