From Community Help > Repositories, Software in Ubuntu’s repository is divided into four categories or components: main, restricted, universe and multiverse.
- Main: The main component contains applications that are free software, can be freely redistributed and are fully supported by the Ubuntu team.
- Universe: The universe component is a snapshot of the free, open-source, and Linux world. It houses almost every piece of open-source software, all built from a range of public sources.
- Restricted: Proprietary drivers that make it possible to install Ubuntu and its free applications on everyday hardware
- Multiverse: The multiverse component contains software that is not free, which means the licensing requirements of this software do not meet the Ubuntu main component licence policy.
We can understand why restricted components are provided. As the page says,
Our commitment is to only promote free software – or software
available under a free licence. However, we make exceptions for a
small set of tools and drivers that make it possible to install Ubuntu
and its free applications on everyday hardware. These proprietary
drivers are kept in the restricted component. Please note that it may
not be possible to provide complete support for this software because
we are unable to fix the software ourselves – we can only forward
problem reports to the actual authors. Some software from restricted
will be installed on Ubuntu CDs but is clearly separated to ensure
that it is easy to remove. We will only use non-open-source software
when there is no other way to install Ubuntu. The Ubuntu team works
with vendors to accelerate the open-sourcing of their software to
ensure that as much software as possible is available under a free
However, why is the multiverse category included? What is the purpose of it?
There is wide range of non-free/proprietary applications & software included in the multiverse category. I don’t understand why this is considered a good thing.