$ git clone -n https://src.fedoraproject.org/rpms/rubygem-nio4r.git /var/lib/mock/f45-build-35063-693/root/chroot_tmpdir/scmroot/rubygem-nio4r
Cloning into '/var/lib/mock/f45-build-35063-693/root/chroot_tmpdir/scmroot/rubygem-nio4r'...
$ git fetch origin 7ba4cfccda5b016ce510567a642d46163a17df9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-nio4r
 * [new ref]         7ba4cfccda5b016ce510567a642d46163a17df9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7ba4cfc Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild