$ git clone -n https://src.fedoraproject.org/rpms/rubygem-multipart-post.git /var/lib/mock/f45-build-35033-693/root/chroot_tmpdir/scmroot/rubygem-multipart-post
Cloning into '/var/lib/mock/f45-build-35033-693/root/chroot_tmpdir/scmroot/rubygem-multipart-post'...
$ git fetch origin 0cf5af0282533efddab6f6fdd6e9dcc0c017c122:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-multipart-post
 * [new ref]         0cf5af0282533efddab6f6fdd6e9dcc0c017c122 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0cf5af0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild