If I were to make a list of useful things Firebug would be right up there with seat belts, calculators, sun screen, and forks. Today I found myself chasing a piece of data while tracking down an elusive bug in unfamiliar code when <cfcookie> stopped me dead in my tracks.
First stop with any problem is Google (add that to the list of useful things) which provided a list of hundreds of cookie tracking tools. After much deliberation I wound up selecting “Firecookie 0.7″ by Jan Odvarko.
Thus far I have to say I like it. Firecookie fits nicely into Firebug 1.3.1 without making me think about where to go find it. Cookie events get logged to console so I can see when cookies are created and deleted. The cookie tab lets me see all relevant cookies, add my own cookies, or delete current cookies. Just what I needed.
https://addons.mozilla.org/en-US/firefox/addon/6683

Much thanks to Jan Odvarko!