I’m investigating category views on wikipedia.
Motivating story: Question - Imagine that I am a STEM educator and wanted to get a complete list of all on-topic categories, subcats, and page ids for just STEM articles on wikipedia. How would I do that?
categorylinks table is a non starter, as it’s too over categorized. Eg: botany->plants->coats of arms with plants.
I’ve proposed this in several different places: Wikipedia:Village pump (policy) - Wikipedia - Response check out portals, wikidata
h*ttps://www.wikidata.org/wiki/Wikidata:Project_chat#Is_there_a_way_to_get_all_STEM_pages_on_wikipedia? - Response - checkout wikiprojects
h*tps://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Council#Get_a_complete_list_of_STEM_categories,_their_subcategories,_and_page_ids - Response - checkout wikipedia categories 
h*tps://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Portals#Get_a_complete_list_of_STEM_categories,_their_subcategories,_and_page_ids - response, none so far
h*tps://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Is_there_a_way_to_get_all_STEM_pages_on_wikipedia? - response none so far