I've created a custom wrapper for the Canvas javascript files that Flash publishes. I've noticed that the root class takes on the name of FLA file and not the JS file. For example, I have SuperCoolGame.fla and I publish it to SuperCoolGame.js, I know I need to create an isntance of lib.SuperCoolGame as my root element. However if I make a copy of the fla, say SuperCoolGamev2.fla and publish it again to SuperCoolGame.js, the root element contructor is now lib.SuperCoolGamev2 instead of SuperCoolGame.
I think it makes more sense to use the js filename as the class name, or possibly have it configurable through the publish dialog like the library and createjs instance names are.