Packages (was: copy large files in Rev on Mac)

[Chipp Walters]

So, I mistakenly thought only .bundle extensions on folders were
bundles-- but, you're saying there are others as well? I've 2
questions:

1. What is the factor which determines whether a folder is treated like a file?

2. How do you Mac guys handle this? IOW, when you walk through a
folder copying, reading or moving files, how do you know whether or
not you're looking at a folder or a file?