The JS debugger allows you to inspect scripts and labels...
How do I access it?
Enter cheat mode and then use cheat code "jsdebug".
Script tabs
Each scripting environment has it's own tab (the bit after the ":" is the value of 'me' for that script):
All enumerable variables on the global scope are listed.
Evaluation box
You can type JS code in to the panel below the globals list and click the Run button to evaluate that code against the global scope in the context of the global object for the associated script environment.
Any errors generated will be echoed to the console.
Triggers tab
Labels tab
The labels tab lists all known Labels on your local machine – it won't list labels on network peers in a multiplayer game.
When a label is selected, you can click the Show button to highlight the area or position on the map associated with the label (which internally uses hackMarkTiles()) as shown below: