Hacking Are all non-U8 compressed .app files DOL executables?

[HNKii]

Almost in every wad I have unpacked seemed to have a un-extractable 00000001.app file
And such files are too large to be stubs.
I'm just asking if any .app files used encryption methods other than U8 by any means?

 

[Antidote]

Some are ASH0 compressed (extremely rare)
It doesn't necessarily mean it's an executable, if you think it might be, plop it into a hex editor and check for "Metrowerks"