coolreader (e-book reader)

CoolReader is an e-book reader for various platforms.

Supported file formats include plain text, HTML, RTF, Microsoft Word
(.doc), Palm Pilot (.prc, .pdb, .pml, .mobi), FB2, and EPUB.

Optional dependencies: The default user interface is Qt4, which
doesn't require anything extra. If you prefer Qt5 or wxWidgets:

qt5 - install qt5, then run: GUI=qt5 ./coolreader.SlackBuild

wx - install wxPython or wxGTK3 (last one installed 'wins'), then run:
     GUI=wx ./coolreader.SlackBuild

Note: coolreader is "chatty": it logs a lot of meaningless warnings
and errors to stderr. Unless there's an actual problem with the
application, you can ignore this stuff.