Newbie: CS6 fla names

Done lots with Flash 8 pro and now trying to understand classes and CS6. When I do file > new > ActionScript3 > OK, it creates Untitlted-1. If I then save it without changing the name, the name at the top becomes Untitled-1.fla:CheckDB. Now I was playing around with one of my AS2 programs called CheckDB but how does that relate to this new program?

Maybe that’s the name of the folder it saved the file in. But in general the two FLAs are / would be unrelated.

Thanks but no, it’s saved in a folder called fla.