> Why, for instance, did it suddenly decide that <i>these</i> particular chunks should be aligned to four bytes, and that this alignement should <i>not</i> be included in the size? Other chunks in other places are either unaligned, or aligned with the alignment included in the size.<p>This sounds like a spec that grew organically, with multiple people contributing to it over the years; the alignment might've come from PowerPC/68k-based Macs, as also evidenced by the use of big-endianness throughout.