> Unfortunately 4.3.6 does not have MUST/MAY wording so we don't really know if this reading was intended by the authors It's not explicit from the APPNOTE, bu

> Unfortunately 4.3.6 does not have MUST/MAY wording so we don't really know if this reading was intended by the authors It's not explicit from the APPNOTE, but that's not the same as saying "we don't really know". We do know—islands of opaque data are allowed and that's the entire reason the format is designed the way it is. Katz designed ZIP for use on machines with floppy drives, and append-only modification of archives spanning multiple media was therefore baked into the scheme from the very roots. He also an produced an implementation that we happen to be able to check, and we know it works that way. The only way to arrive at another interpretation is to look at APPNOTE in isolation and devoid of context. > one could argue that this is not necessarily to state, that there is only one EOCDR by definition, and that any previous ones are just garbage data that is to be ignored That is the correct interpretation; the wording doesn't suggest otherwise.