Distribution meta information contains such items as name, version, abstract and many others. All named items are written to META.json (and maybe to META.yml) automatically, all you need is just using
MetaYAML plugin(s) in your dist.ini file.
Meta information may also include description — a longer, more complete description of the distribution. However,
Dist::Zilla does not provide option to specify description. It could be easily fixed with