Rated 5 out of 5 stars
Fantastic add-on. I spent several months working with a designer and developer on the website redesign at the museum I work for - this tool made the process infinitely easier.
Rather than having to search through the regular "view source" textfile for the one needle in the code haystack to see what's going on, this cool little add-on breaks it down into color blocks, making it easy to find what you're looking for - a must for a very visual person like me.
Another plus is that as someone with a fairly rudimentary grasp of HTML, it makes learning how the structure of the page works easier too.
Win-win. One of my personal "Must Have" add-ons.