There is no need to write all of this. It’s simply about adding [“r”, “url”, “canonical”] tag, and web clients will read them to display canonical links (in ui and the html). Details about security, etc., are also relevant (all explained in nip). While it’s not particularly authoritative in Google, it remains a standard approach. I am building jotstr.com, so I am striving to align with established standards.

https://www.rfc-editor.org/info/rfc6596/ (canonical rfc)