Emacs hashtag bracket(#[]) notation

Question

When choosing a project using helm-projectile-switch-project one can type C-d to run dired on that project root directory.

Running describe-key on C-d returns the following function:

#[nil "\300\301!\207" [helm-exit-and-execute-action dired] 2 nil nil]

Any pointers on where I can read about on how to make sense of this notation? This looks like a "printed notation", yet I'm unable to find it in the docs.

Answer 1

This is the printed notation of compiled emacs lisp byte-code, you can read more about it in the manual.

This post will probably be more helpful with understanding what is represented in the vectors you see.