What is the node repl outputting here?

What are all these properties? Are they properties or methods or what? They look like labels. super_, fail, equal (equal to what?), deepequal, what do they mean? How do you access these properties|methods|whatever they are called? Are they specific to node?

// $ node #start the node repl 
// > assert //outputs the below
{ [Function: ok]
  AssertionError: 
   { [Function: AssertionError]
     super_: 
      { [Function: Error]
        captureStackTrace: [Function: captureStackTrace],
        stackTraceLimit: 10 } },
  fail: [Function: fail],
  ok: [Circular],
  equal: [Function: equal],
  notEqual: [Function: notEqual],
  deepEqual: [Function: deepEqual],
  notDeepEqual: [Function: notDeepEqual],
  strictEqual: [Function: strictEqual],
  notStrictEqual: [Function: notStrictEqual],
  throws: [Function],
  doesNotThrow: [Function],
  ifError: [Function] }