The "deep" explanation of how this was achieved can be found on Russ Cox's research site, research!rsc .
: This is a "quine" zip file—a recursive archive that contains a copy of itself. When you open r.zip , it contains another file also named r.zip , which contains another r.zip , and so on, theoretically forever. The Deep Blog Post Download 102k zip
: Cox walks through the byte-level construction, including how to handle the checksums (CRCs) that would normally change when the file's content changes. The "deep" explanation of how this was achieved
: The post explains how to construct a zip file that contains its own exact bytes. This is done by exploiting the structure of zip files, specifically how they use "Local File Headers" and "Central Directories" to point to data offsets. The Deep Blog Post : Cox walks through