In this expression:
(car (quote (quote abracadabra)))
=> 'quote
The inner quote
doesn't get evaluated, it's just a symbol, with no particular meaning. You might as well change it for anything else, with the same results:
(car (quote (foobar abracadabra)))
=> 'foobar
Inside a quoted expression, other expressions won't get evaluated. We could use quasiquoting to force evaluation, now this will attempt to evaluate the inner quote, resulting in a different error for each case:
(car (quasiquote (unquote (quote abracadabra)))) ; (car `,(quote abracadabra))
=> car: contract violation expected: pair? given: 'abracadabra
(car (quasiquote (unquote (foobar abracadabra)))) ; (car `,(foobar abracadabra))
=> foobar: unbound identifier in module in: foobar