That's not a "canonical" site either. That's the domain name of "Digital Millennium Copyright Act Services Ltd.", a company which deliberately (and annoyingly) takes the same name as the Digital Millennium Copyright Act for SEO purposes. They don't want you to file your own DMCA requests, even though you can. They want you to fall for their trick of searching for "DMCA", and to use their services.
The canonical location to find the DMCA is the United States legislation, specifically the Statues at Large. On the other hand, the best place to find the DMCA online would probably be https://www.govinfo.gov/app/details/PLAW-105publ304 , which offers downloads in multiple formats. This is also linked from the Wikipedia article that was offered before.
Always check the "External Links" and "References" sections of a Wikipedia article if you're looking for canonical sources like this!
Self-correction: I meant the "Statutes at Large". (I'd edit, but HN doesn't let you edit comments after a certain amount of time, and I only just noticed this mistake.)
I'm not a fan!