Hi folks,
as of yesterday, the CommonsMetadata extension is active on all wikis. As the name suggests, it's optimized for providing API access to metadata for files on Commons, but it will also work for project-local uploads (e.g. fair use metadata on en.wp) -- provided that the templates used for describing metadata emit the same machine-readable information.
The format for emitting such machine-readable metadata is documented here: https://commons.wikimedia.org/wiki/Commons:Machine-readable_data
The documentation page for the extension (which could use some cleanup & examples BTW) is at: https://www.mediawiki.org/wiki/Extension:CommonsMetadata
Help modifying local templates accordingly is appreciated.
All best, Erik