This is an independent DIY search engine that focuses on non-commercial content, and attempts to show you sites you perhaps weren't aware of in favor of the sort of sites you probably already knew existed.
The software for this search engine is all custom-built, and all crawling and indexing is done in-house.
This search engine isn't particularly well equipped to answering queries posed like questions, instead try to imagine some text that might appear in the website you are looking for, and search for that.
Where this search engine really shines is finding small, old and obscure websites about some given topic.
REST API: https://memex.marginalia.nu/projects/edge/api.gmi
E-mail the admins for an API key.