I should have been more precise.
You should take some of the files from ROOT.cvm, open them in hex editor, and try to see what's in the header.
You might find a clue as to what kind of files they are.
Besides, even if you want to see some REAL TEXT, in those files... you need a, well... table file for your hex editor.
That, you usually need to make yourself.
Tough, I dunno how.
Oh, and header is, obviouslly, at the beginning of the file.