Hm, the site has changed since I saw it last, seemingly to only include automated API documentation. That's a shame. IIRC it's the Article Search API - it has

Hm, the site has changed since I saw it last, seemingly to only include automated API documentation. That's a shame. IIRC it's the Article Search API - it has a field named "fl" that controls what fields are returned, but it now the documentation doesn't seem to specify what fields it can return.