One value that would be useful that exists in the current PyPi JSON API but not in this spec or the metadata is the upload time.
It would be useful to standardize this feature so when resolvers are doing an initial solve it’s possible to offer the feature “don’t get packages uploaded more than 5 years ago” or “prioritize based on recent upload time”.
While the spec is only about reproducing the Simple Repository API in JSON my and allows for future enhancements my concern is that because the spec states “Additional keys may be added to any dictionary objects in the API responses” that implementations may add their own custom upload time key before there is a standard agreed name and format.
Not a big deal, just a thought.