A file with .wmz extension is a compressed version of WMF and is used to store metafiles. It is an intermediate level file generated by older versions of Microsoft Office applications and is not very popularly used. WMZ files are generated while saving documents to HTML format. These may also be generated while emailing documents that contain embedded clip art, equations, etc. Applications that can open WMZ files include (but not limited to) Corel Winzip and Apple Archive Utility.
WMZ File Format
WMZ files are Gzip compressed and contains WMF inside. Gzip uses the DEFLATE algorithm for compression of the archive. GZIP is different from the ZIP archive format as it applies compression algorithm to complete archive rather than the individual files. The file format consists of:
The GZIP file format specifications version 4.3 published by Internet Engineering Task Force (IETF) contains detailed information about the file format.