The page http://xmlns.com/foaf/spec/ discusses the FOAF vocabularies. Details of the terms are discussed in the same page (e.g. http://xmlns.com/foaf/spec/#term_Person).
But if I am looking for the actual rdfs
code of a class or property, where do I get it?
Surprisingly, a web search has not produced anything. The textbooks contain some class and property codes, but they are mostly outdated, as expected.
In the header of http://xmlns.com/foaf/spec/, there are links to the various versions, including links to RDF/XML serializations, e.g. currently:
As explained in the "Status of This Document" section, you can also get the RDF/XML document via content negotiation:
And some parts are included in the HTML via RDFa: