Hello.
When I evaluate "(pp esc-map)" it pretty-prints a keymap that starts with
the lines

(keymap
 #^[nil nil keymap
    #^^[3 0 mark-sexp beginning-of-defun backward-sexp ...

...and so on

Can someone explain this syntax?
eg Why is keymap the 3rd element in the char-table, and what does the "nil
nil" before it signify?
What is "#^^[3 0" ? What do the 3 and 0 mean here?

why does "(aref (nth 1 esc-map) 0)" return "mark-sexp"?

I couldn't find answers in the manuals for emacs or elisp, except maybe
that "#^[ nil nil keymap" means character code 3 corresponds to a keymap in
this char-table

-HD