In case you're trying to open the RFC links on the site, the IETF site no longer supports http and does not redirect to https, hence you see a 404 error. You can manually open https versions of the urls to visit them

JSON Patch - https://datatracker.ietf.org/doc/html/rfc6902 JSON Pointer - https://datatracker.ietf.org/doc/html/rfc6901

Tried PR'ing to fix site, but repo didn't seem active