The add-on looks and controls great. I had two problems with it:

⦁ It doesn't hyphenate words, which, with justified texts, leaves wide gaps. I know that the problem may be not with the add-on but with the document's CSS not including hyphenation preset. On my desktop and smartphone readers text is hyphenated, so I guess it depends on the reader apps too.🤷🏻‍♂️

⦁ It failed to load images. It may be because the images are vector (.svg). If I click on them and hit "Open image in a new tab", the image loads. I haven't tried replacing .svg's with raster images, but I assume the add-on has no problems with them.

I can't go on the pages in the opened book.

Doesn’t work

good tool but drag and drop option for file opening would be nice to avoid time intensive searching in open dialog. Flaws with fullscreen mode (white empty areas at bottom with dark background). Read aloud addon does not work properly with this reader. (might be a Read aloud problem)

Works good

Simply does not add a button to open already existing epub files. Something must be broken. Doesn't appear when I try to customize my buttons, either.

This is good for those who can't find a good standalone ePub reader and it monitored by Mozilla. I like dark mode with white text which is easy on the eyes. Furthermore, Read Aloud can read from it. Although great, I think an update is overdue. I would like a history of files previously opened.

Can not open downloaded file