Okular is a universal document viewer developed by KDE. Okular works on multiple platforms, including but not limited to Linux, Windows, Mac OS X, *BSD, etc.
- Supported Formats: PDF, PS, Tiff, CHM, DjVu, Images, DVI, XPS, ODT, Fiction Book, Comic Book, Plucker, EPub, Fax
- Sidebar with contents, thumbnails, reviews and bookmarks
- Annotations support
GPL-2.0+ and GFDL-1.3.