> Additionally, the "deflate" compression likely does not span across files Clarification: .zip (unlike .tar.gz for example, or "solid" .7z) compresses each fi

> Additionally, the "deflate" compression likely does not span across files Clarification: .zip (unlike .tar.gz for example, or "solid" .7z) compresses each file separately, that's nothing to do with the compression algorithm used. In addition, DEFLATE, the LZ77-based compression which is by far most commonly used in .zip (and also by gzip) has a window size of 32kB (uncompressed). So yes, even if you used DEFLATE on a solid stream (e.g. zipped a .tar archive) it couldn't remove any cross-file redundancy once it's gone past the first 32kB of each file.