Is it possible to convert .htmlz files to .epub format.
Converting Zipped HTML eBooks directly to Open eBook Files (.htmlz to .epub format) is possible and quite straightforward, since most modern ebook conversion tools support both file types.
Try, for instance, Calibre or Hamster eBook Converter, which allow users to easily convert .htmlz to .epub format.
Alternatively, you can try some online conversion tools.