Okular is a universal document viewer based on KPDF for KDE 4. This
means Okular works on multiple platforms, including but not limited to
Linux, Windows, Mac OS X, *BSD, etc.

Okular combines the excellent functionalities of KPDF with the
versatility of supporting different kind of documents, like PDF,
Postscript, DjVu, CHM, XPS, ePub and others.

WWW: https://okular.kde.org