https://en.wikipedia.org/w/api.php?action=query&list=categorymembers&... seems to work fine.
If i were to guess why its not on list=projectpages, id say that wikiproject democratic republic of the congo is not a full on wikiproject itself but just a subproject of wikiproject africa.
-- brian
On Saturday, February 17, 2018, Bowen Yu bowen-yu@umn.edu wrote:
Hi, I am trying to get articles belong to WikiProject Democratic Republic of
the Congo. I tried both API calls and Quarry (I guess they shared the same data source), but did not get any articles back. I wonder if anyone has any sense what's going for this project in the database? I just used "Democratic Republic of the Congo" as the query input. Thank you!