[Feature Request] Support for adding references to Wikidata.org statments.

[ElanHR]

Similar to Wikipedia passages, individual Wikidata statements are often missing proper references and could benefit from a similar workflow.

I would be happy to try and implement this but would love any pointers of how/where to add this given the existing codebase. :)

[eggpi]

Hey Elan, thanks! This sounds like a good feature and it will be awesome if you get a chance to contribute :)

Your first step should probably be the CONTRIBUTING.md file, which will tell you how to set up a local CH for development.

Very broadly speaking, the way CH works is:

1. Expand a certain category to find all articles with {{cn}} tags.
2. Parse all articles to extract snippets, write the page ids and snippets to a database.
3. Load all the categories for the articles, write those into the database too.

This is all driven by cron jobs in the scripts/ directory. I don't know much about Wikidata but conceptually I'd start by trying to figure out what the three steps above mean in this case: is there a way to get all unsourced statements on Wikidata? How do we present a statement to the user? Are there interesting groupings (like categories) of statements that we might want to load?

[lydiapintscher]

If we want to focus on statements that are most in need of a citation the it probably makes sense to look at the "citation needed"-constraint. The date of birth property for example has one: https://www.wikidata.org/wiki/Property:P569#P569$960c1d3c-4198-6f97-ee00-899f149c0a7e
Any statement with that property that doesn't have a reference then triggers a constraint violation warning like on the Item about me here: https://www.wikidata.org/wiki/Q18016466#P569