EDU backlinks refer to links obtained on website domains with EDU extension.
With GOV backlinks, EDU links are the “holy grail” of a netlinking strategy. Indeed, EDU domains, and therefore EDU backlinks, have authorithy and trust in the eyes of Google and other search engines.
Like EDU backlinks, GOV backlinks are particularly sought after by SEO professionals because they have authority and trust from Google. Google probably considers GOV websites merit authority due to their nature and because they have often very high number of backlinks. Of course, the EDU extension is restricted to government agencies.