Today a client suggested that the Devel module Krumo could display the "path" to an item in an array by right clicking or otherwise interacting with the nested elements in the output from Krumo. I was really excited about that idea - I can't count the number of times I have tried and failed to target an item deep in a form array or an item in the node object simply because my human brain can't remember a structure like
$form['#node']->content['links']['comment']['#attributes']['class'] for more than 3 seconds.
Thanks to Niels Fanøe for the inspiration.
EDIT: I was using the dev D7 version, and the feature just went in this August. Thanks to Mark Theunissen for pointing that out. I also feel less stupid for not discovering the feature before now!