"DuckDuckGo's results are a compilation of "over 400" sources,[45] including Yahoo! Search BOSS; Wikipedia; Wolfram Alpha; Bing; its own Web crawler (the DuckDuckBot); and others.[3][45][46] It also uses data from crowdsourced sites, including Wikipedia, to populate "Zero-click Info" boxes – grey boxes above the results that display topic summaries and related topics.[10]"

- https://en.wikipedia.org/wiki/DuckDuckGo#Overview - https://duck.co/help/results/sources