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Ubuntu Policy Manual
Chapter 2 - The Ubuntu Archive

The Ubuntu system is maintained and distributed as a collection of packages. Since there are so many of them (currently well over 15000), they are split into sections and given priorities to simplify the handling of them.

The effort of the Ubuntu project is to build a free operating system, but not every package we want to make accessible is free in our sense (see the Ubuntu Licensing Policy, below), or may be imported/exported without restrictions. Thus, the archive is split into areas[3] based on their licenses and other restrictions. We also divide up packages based on whether they are supported or not.

The aims of this are:

2.1 The Ubuntu Licensing Policy

The Ubuntu Licensing Policy forms our definition of "free software". The following guidelines apply to the main and universe categories of the archive:

Must include source code.

The main and universe categories have a strict and non-negotiable requirement that application software included in them must come with full source code.

Must allow modification and distribution of modified copies under the same license.

Just having the source code does not convey the same freedom as having the right to change it. Without the ability to modify software, the Ubuntu community cannot support software, fix bugs, translate it, or improve it.

The following additional guidelines apply to the main, restricted and universe categories of the archive:

Must allow these rights to be passed on along with the software.

You should be able to have exactly the same rights to the software as we do.

Must not discriminate against persons, groups or against fields of endeavour.

The license of software included in Ubuntu can not discriminate against anyone or any group of users and cannot restrict users from using the software for a particular field of endeavour - a business for example. Thus we will not distribute software that is licensed "freely for non-commercial use".

Must not be distributed under a license specific to Ubuntu.

The rights attached to the software must not depend on the programme's being part of Ubuntu system. So we will not distribute software for which Ubuntu has a "special" exemption or right, and we will not put our own software into Ubuntu and then refuse you the right to pass it on.

The following additional guidelines apply to the entire archive:

Must allow redistribution.

Your right to sell or give away the software alone, or as part of an aggregate software distribution, is important because:

Must not require royalty payments or any other fee for redistribution or modification.

It's important that you can exercise your rights to this software without having to pay for the privilege, and that you can pass these rights on to other people on exactly the same basis.

Must not contaminate other software licenses.

The license must not place restrictions on other software that is distributed along with it. For example, the license must not insist that all other programmes distributed on the same medium be free software.

May require source modifications to be distributed as patches.

In some cases, software authors are happy for us to distribute their software and modifications to their software, as long as the two are distributed separately, so that people always have a copy of their pristine code. We are happy to respect this preference. However, the license must explicitly permit distribution of software built from modified source code.

The "GPL," "BSD," and "Artistic" licenses are examples of licenses that we consider free.

Ubuntu contains licensed and copyrighted works that are not application software. For example, the default Ubuntu installation includes documentation, images, sounds, video clips and firmware. The Ubuntu community will make decisions on the inclusion of these works on a case-by-case basis, ensuring that these works do not restrict our ability to make Ubuntu available free of charge, and that Ubuntu remains re-distributable by you.

2.2 Archive areas

2.2.1 The main archive area

Every package in main must comply with the Ubuntu Licensing Policy.

In addition, the packages in main

2.2.2 The restricted archive area

Every package in restricted must comply with the Ubuntu Licensing Policy, with the exceptions that source code may not be available and that modification may not be permitted.

In addition, the packages in restricted

The Ubuntu team recognises that many users have vital hardware in their computer that requires drivers that are currently only available in binary format. We urge all hardware vendors to insist that their suppliers provide open source drivers for their components, but we recognise that in some cases binary drivers are the only way to make your hardware work. As a result, Ubuntu includes several of these drivers on the CD and in the repository, clearly separated from the rest of the software by being placed in the restricted archive area.

Binary drivers are a poor choice, if you have a choice. Without source code, Ubuntu cannot support this software, we only provide it for users who require it to be able to run the Free Software we provide in main. Also, we cannot make binary drivers available on other architectures (such as the Mac or IPAQ) if we don't have the ability to port the software source code ourselves. If your hardware is fully supported with open source drivers you can simply remove the restricted archive area, and we would encourage you to do so.

The restricted archive area may not include application software, only hardware drivers.

2.2.3 The universe archive area

Every package in universe must comply with the Ubuntu Licensing Policy.

Packages in the universe archive area are not supported by the core Ubuntu developers and Canonical Ltd. Packages may be moved between main and universe as their support status changes.

In addition, the packages in universe

2.2.4 The multiverse archive area

Every package in multiverse must comply with the Ubuntu Licensing Policy, with the exceptions that source code may not be available, that modification may not be permitted, that rights may not be passed on along with the software, that they may discriminate against persons, groups or fields of endeavour, and that their license may be specific to Ubuntu. (In other words, they must be redistributable without a fee and must not contaminate other software licenses.)

Packages must be placed in multiverse if they are not compliant with the parts of the Ubuntu Licensing Policy that cover other categories of the archive, or if they are encumbered by patents or other legal issues that make their distribution problematic.

Packages in the multiverse archive area are not supported by the core Ubuntu developers and Canonical Ltd.

In addition, the packages in multiverse

2.3 Copyright considerations

Every package must be accompanied by a verbatim copy of its copyright and distribution license in the file /usr/share/doc/package/copyright (see Copyright information, Section 12.5 for further details).

We reserve the right to restrict files from being included anywhere in our archives if

Programs whose authors encourage the user to make donations are fine for the main distribution, provided that the authors do not claim that not donating is immoral, unethical, illegal or something similar; in such a case they must go in multiverse.

Packages whose copyright permission notices (or patent problems) do not even allow redistribution of binaries only, and where no special permission has been obtained, must not be placed on the Ubuntu FTP site and its mirrors at all.

Note that under international copyright law (this applies in the United States, too), no distribution or modification of a work is allowed without an explicit notice saying so. Therefore a program without a copyright notice is copyrighted and you may not do anything to it without risking being sued! Likewise if a program has a copyright notice but no statement saying what is permitted then nothing is permitted.

Many authors are unaware of the problems that restrictive copyrights (or lack of copyright notices) can cause for the users of their supposedly-free software. It is often worthwhile contacting such authors diplomatically to ask them to modify their license terms. However, this can be a politically difficult thing to do and you should ask for advice on the ubuntu-archive mailing list first, as explained below.

When in doubt about a copyright, send mail to ubuntu-archive@lists.ubuntu.com. Be prepared to provide us with the copyright statement. Software covered by the GPL, public domain software and BSD-like copyrights are safe; be wary of the phrases "commercial use prohibited" and "distribution restricted".

2.4 Sections

The packages in the archive areas main, restricted, universe and multiverse are grouped further into sections to simplify handling.

The archive area and section for each package should be specified in the package's Section control record (see Section, Section 5.6.5). However, the maintainer of the Ubuntu archive may override this selection to ensure the consistency of the Ubuntu distribution. The Section field should be of the form:

The Ubuntu archive maintainers provide the authoritative list of sections. At present, they are: admin, cli-mono, comm, database, devel, debug, doc, editors, electronics, embedded, fonts, games, gnome, graphics, gnu-r, gnustep, hamradio, haskell, httpd, interpreters, java, kde, kernel, libs, libdevel, lisp, localization, mail, math, metapackages, misc, net, news, ocaml, oldlibs, otherosfs, perl, php, python, ruby, science, shells, sound, tex, text, utils, vcs, video, web, x11, xfce, zope.

Ubuntu: The metapackages section exists for the benefit of package management tools. When removing a package in that section, its dependencies will not be automatically considered for removal by tools which track the distinction between packages that were installed explicitly and packages that were only installed to satisfy dependencies.

2.5 Priorities

Each package should have a priority value, which is included in the package's control record (see Priority, Section 5.6.6). This information is used by the Ubuntu package management tools to separate high-priority packages from less-important packages.

The following priority levels are recognized by the Ubuntu package management tools.


Packages which are necessary for the proper functioning of the system (usually, this means that dpkg functionality depends on these packages). Removing a required package may cause your system to become totally broken and you may not even be able to use dpkg to put things back, so only do so if you know what you are doing. Systems with only the required packages are probably unusable, but they do have enough functionality to allow the sysadmin to boot and install more software.


Important programs, including those which one would expect to find on any Unix-like system. If the expectation is that an experienced Unix person who found it missing would say "What on earth is going on, where is foo?", it must be an important package.[7] Other packages without which the system will not run well or be usable must also have priority important. This does not include Emacs, the X Window System, TeX or any other large applications. The important packages are just a bare minimum of commonly-expected and necessary tools.


These packages provide a reasonably small but not too limited character-mode system. This is what will be installed by default if the user doesn't select anything else. It doesn't include many large applications.


(In a sense everything that isn't required is optional, but that's not what is meant here.) This is all the software that you might reasonably want to install if you didn't know what it was and don't have specialized requirements. This is a much larger system and includes the X Window System, a full TeX distribution, and many applications. Note that optional packages should not conflict with each other.


This contains all packages that conflict with others with required, important, standard or optional priorities, or are only likely to be useful if you already know what they are or have specialized requirements (such as packages containing only detached debugging symbols).

Packages must not depend on packages with lower priority values (excluding build-time dependencies). In order to ensure this, the priorities of one or more packages may need to be adjusted.

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Ubuntu Policy Manual

version, 2009-06-19

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