Stale / duplicate data

[lsmith77]

In content in .well-known could get outdated or could end up being duplicated on mirrors leading to inaccurate the data.

Possible solutions:

• stale data: add a last updated date field. aggregators could use this information to decide if to trust the data and/or notify the source
• duplicate data: add a canonical URL field. this way the mirror data can safely be ignored and optionally warn if the canonical URL is not available.

[lsmith77]

This also raises the question of how to determine the canonical URL of open source project repositories.