Nodetype dependent code

[JCR]

Hi,

I recently noticed on Lars' cheatsheet 
(http://dev.day.com/docs/en/cq/current/developing/sling_cheatsheet.html), step 
# 3, the term "Last resort".

I'd interpret this as possibility to attach specific code to a given 
nodetype, i.e. scripts, or perhaps even bundles, could be linked to a 
Nodetype. Now, I didn't find documentation on this specific topic.

So, my questions are:
It above assumption correct? If yes, where would I need to place the 
code so it gets recognized by Sling to belong to nodetype X?

Thanks Pros,
Juerg