Vitsy, 4 bytes

This language feature is newer than this question, but not made for this question.

iG`Z

i     Grab input. Since there is no input, it pushes -1 to the stack.
 G    Get the class name of the referenced class. -1 refers to the current class.
  `   Read the file under the name of the stack's contents and push all of it to the stack.
   Z  Output everything in the stack.

As of November 24, class commands allow for referencing other programs accessible by disk, or 'classes'. Normally, it'd be used something like this:

00k

;use;u someothervitsyfile

Where I execute the 0th line (the first line) of the 0th index of the uses list ('someothervitsyfile'). I can get its name with G like so:

0GZ

;use;u someothervitsyfile

And, if I have the name, I can get its contents like so:

0G`Z

;use;u someothervitsyfile

But the special cases of this are -2 and -1, where -2 references the superclass (as defined by ;ext;e) and -1 references the current class.

So, to get the name of the current class, I use -1, get its name, and, with its name being the only thing in the stack, I pull its contents with `.

Very fancy.

You cannot try this online, as it has been disabled to prevent reading server files.