Difference between Ubuntu apt main universe restricted multiverse repos:

The main, universe, restricted, and multiverse repositories are the four official software repositories in Ubuntu, each serving a distinct purpose based on licensing and support.

Main: Contains officially supported, open-source software. Canonical provides critical updates and support for packages in this repository. Is the only eligible repo for Ubuntu Pro (extended support). This repo must be registered in order to build or upgrade a ubuntu-minimal complaint system.
Universe: Houses community-maintained open-source software that is not officially supported by Canonical. While not directly maintained by Canonical, some updates may be provided by the Ubuntu community. This is needed for Ubuntu "flavors" outside of the main desktop and server editions of Ubuntu. Such as Ubuntu versions with a different DE like Kubuntu, Lubuntu and even Ubuntu Unity since Canonical abandoned the Unity DE despite creating it. Also opens a large library of additional software to users.
Multiverse: Includes software that is not free, often restricted by copyright, patents, or other legal issues and is a mix of open-source and freeware software. Canonical does not provide updates for these packages, and they are typically not included in the default installation. They might be mostly open-source but contain non-FLOSS compliant licenses or are media codecs. Some examples are software related to Google like the Android SDK/Drivers. Some Oracle software like Virtual Box. Media Codes (ubuntu-restricted-extras) since media codecs under 20 years are still patted protected (in the USA) causing legal issues. Some fonts from Microsoft Windows and IBM Plex are also here and other fonts as well.
Restricted: Contains free proprietary software (more long the lines of freeware then floss) that is supported by Canonical but not available under a completely free license, such as certain hardware drivers. A very small repo and mostly its just Broadcom wireless drivers and NVIDIA GPU drivers. It goes agents the FLOSS license model that will upset many Linux users but Canonical thinks its good to still provide due having a working computer is more important then politics. It is also restricted to what ever ISA that binary is compiled too.

If your want to look at what each repo has, you can use the GUI APT tool "Synaptic Package Manager" and under the Origin tab view the contents for each repo.

Date: November 22nd 2025 @ 5:50am.

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