Most Apple applications do use bundles extensively, but that has nothing to do with HFS+.<p>Apple has religiously avoided <i>"use of bit-twiddling in the HFS+ filesystem"</i> for years -- everything new since 10.4 uses standard extended attributes. The only remaining uses I can think of are Finder color labels (a special bit-field in HFS), and that a bunch of the standard fonts still use resource forks (they only have a license to redistribute).