.HTMLZ File Extension
File TypeZipped HTML eBook
This file is saved in a zipped format. You can view the contents by unzipping it with a file decompression program.
What is an HTMLZ file?
File that contains an eBook saved in the HTMLZ format, which is a .ZIP file with the ".htmlz" extension; contains multiple files, including .HTML files, images, and a metadata.opf (.OPF) file; used for packaging eBook content into a single archive.