alt Hacker NewsI'm not aware of any, but it wouldn't be insane to build a seekable deflate implementation by defining offsets in a zip comment. This would leave the zip file backwards compatible to usual decompression while allowing internal seeking within an individual file if the decompressor was aware of this index.
For seekable gzip indexes in zip, there SOZip: https://github.com/sozip/sozip-spec . However, it stores the indexes as files succeeding the actual file entry. To hide these index files and avoid extraction, they are not listed in the central directory, but a linear scan of the local headers, which some wrongly-behaved ZIP tools do, or which might be necessary for recovering broken ZIP files, would find those hidden indexes.