Thunderbird, on the other hand, has very little in the way of developer tools. We used to have ChromeBug, but then that project went by the wayside when the Firebug developers decided to focus more on, well, Firebug.
And ever since, debugging and fiddling around in Thunderbird has been a pain.
So a few folks on the TB team decided to take a crack at porting one of Firefox’s tools to Thunderbird. We chose Scratchpad (or rather, its earlier incarnation, “Workspace”), because being able to execute snippets of script on the fly is super-useful for trying stuff out.
So without further ado, here it is – Workspace for Thunderbird.
Install that, and a new Workspace menuitem appears under Tools. This will open up Workspace. Make sure to switch your Context to Chrome for superpowers.