epbvr, a crude featureless single file offline epub viewer.

Save/copy the epbvr.html somewhere.
Open it on a browser.
Choose an epub file to view.
Refresh/reload to open another file.

epbvr uses/includes the epub.js (license) library,
and the JSZip (license) library, which uses the pako (license) library.
The remaining code of epbvr (not already covered by the previous licenses)
is released under the MIT license (see source code lines 122-146).