Lubuntu is a complete Operating System that ships the essential apps and services for daily use: office applications, PDF reader, image editor, music and video players, etc.
Lubuntu now ships the most advanced desktop interface, using Qt technologies for rendering the widgets and the entire ecosystem (from the installer to the smallest parts).
Arc theme and the Papirus icons' winning combination makes the new Lubuntu desktop easier to read and less cluttered. The symbolic icons and glyphs, now easier to recognize, added to sharp edges and vibrant colors, add visual dynamics without overwhelming the overall design.
Combined with the new compositing effects, the apps, panels, and widgets of your new desktop will look modern while being fast, simple, and affordable for almost every machine.
Lubuntu is compatible with most existing file formats, such as images, songs, films, spreadsheets, text documents, internet radio stations, and much more.
Everything works out of the box. But if you need more (usually proprietary) codecs for exotic file formats, you can always install the ubuntu-restricted-extras package and enjoy all that content.
And there is more in the Software Center. Just look for the file format or application you need and get it for free.