If you want a simple, easy and fast ebook reader for .epub files (.mobi sadly aren’t support), I can really recommend mupdf.
Thank you for your advice, however, I prefer Calibre which is on GPLv3 contrary to mupdf which is owned by Artiflex company.
MuPDF is indeed copyrighted by Artifex Software Inc., but it is released under AGPLv3.
Miraki thinks this is malware-related (probably some dumb work setting), but also Firefox is kvetching about SSL.
Could you please tell more about that by private message? How do you get the report?
Thank you very much,