Ubuntu-restricted-extras
Ubuntu Restricted Extras is a software package for the computer operating system Ubuntu that allows the user to install essential software which is not already included due to legal or copyright reasons. It is a meta-package that installs: Background. The software in this package is not included in Ubuntu by default because Ubuntu maintainers want to include only completely free software in out-of-the-box installations. The software in this package may be closed-source, encumbered by software patents, or otherwise restricted. For example, the Adobe Flash plugin is a closed-source piece of software . Additionally, many multimedia formats such as MP3 and H.264 are patented. In countries where these patents apply, legally distributing software that use these formats may require paying licensing fees to the patent owners. Contents. The Ubuntu Restricted Extras is a metapackage and has the following dependencies: Starting with Ubuntu 10.10, several of these dependencies are included indirectly via another meta-package "ubuntu-restricted-addons" which is included by default. Inclusion. Due to the legal status of the software included in Ubuntu Restricted Extras, the package is not included by default on any Ubuntu CDs. However, some distributions, such as Super  OS, Pinguy OS and Revamplinux do bundle the package on their installation CDs or DVDs. For a listing of the formats offered via this repository, follow the link at the end of this paragraph to help/ubuntu.com, Ubuntu's official online wiki. Note that the above statement DOES NOT imply that the software is pirated or in any way illegal to download. Furthermore, it doesn't imply that Canonical is somehow breaking the law by offering the software. In fact, the _restricted_ repository exists for the sole purpose of making it easier to follow the law in the event that  the software becomes unusable in its current form. That is what is meant by "Due to the legal status...". for an explanation of this concept, see this source.