Locating AS3 resources in a project

Using Flash CS3 and AS3:

Where are the resources located? For instance I have checked out a few samples online and the Main.FLA is empty (with maybe a few movie clips).

There are a few .AS files along with the Main.FLA. Where are these .AS files referenced? There is no ActionScript in Main.FLA according to the Movie Explorer.

If I rename the .AS files, the Main.FLA no longer works, so obviously the names are referenced elsewhere.

Can’t find the .AS files referenced in the Movie Explorer, and of the Movie Clips, the Library… where am I missing the references to the included .AS class files?

Thanks