The spec says filenames are encoded in CP437. UTF-8 filenames are supported as overlays in two different 'extra headers', which essentially amount to vendor-spe

The spec says filenames are encoded in CP437. UTF-8 filenames are supported as overlays in two different 'extra headers', which essentially amount to vendor-specified extensions. There are noncompliant implementations that generate zip files with filenames in ISO 8859-1 and other 8-bit codepages, and conversely, there are decompressors that try to accommodate such malformed files.