Ask HN: Browser/connection fingerprint

What is a good summary of the fingerprint left when loading a page?

-all header values in the request (http headers at application level) -the page can request the "navigator" object which has plugins details (details that can be sent to the server separately) -all values of headers at transport and internet layer

In particular about the latter, is there anyway I can get some info in nodejs? I think not, since nodejs is working at application layer so has no idea of the underlying layers, correct?