I fell into this because I was curious: could I look inside a giant ZIP without downloading the whole thing? That question took me into the guts of the ZIP format, where I learned there’s a tiny index at the end that points to everything else. Once you see that, the whole file starts to feel like a book with a really helpful table of contents. ZIP Architecture Here’s the mental model I carry now: ZIPs are a stack of per‑file records, and then an index at the end that tells you what’s inside and ...