The .zip spec is flawed, but… I've never had an issue with extracting or using a .zip file I'd suggest this is thanks to most software following (to some ext

The .zip spec is flawed, but… I've never had an issue with extracting or using a .zip file I'd suggest this is thanks to most software following (to some extent) the robustness principal: be conservative in what you do, be liberal in what you accept. Most of us will typically encounter fairly well packaged, conforming zip files. Occasionally we may come across something unanticipated - like this example, where HTML content is accidentally appended to the end of a zip file - and I suspect this is where we will find ambiguous behaviour: some package tools may crash, others might "extract" it as though it were content, others might ignore it. It's this area of ambiguity that lends itself to vulnerabilities and attacks. Re: physical engineering, I'd recommend a great book: "To Engineer Is Human". It talks about the evolution of engineering, which is a surprising amount of trial and error, with emphasis on the error.