[KlaymenDK]

> modern Mac application bundles

I just want to say that OLD Mac applications were exactly that, too -- even the OS was basically just "Finder" and "System", that was it. Dragging those two files to a different floppy (and swapping them 12 times to complete the copy) gave you a bootable disk. Meanwhile Windows apps were hundreds of files ... then eventually Mac apps went the same way, although not as wildly.

[AnIdiotOnTheNet]

Yes, it was also used in RiscOS. Even DOS applications were really just a folder. It was a common feature of Desktop OSs of the time.