Ubuntu – What’s the criteria for an application to be included in the Universe repository

From the Ubuntu documentation:

The repository components are:

• Main - Officially supported software.

• Restricted - Supported software that is not available under a completely free license.

• Universe - Community maintained software, i.e. not officially supported software.

• Multiverse - Software that is not free.

For example:

• The Ubuntu Desktop team manages the gnome-terminal package, it is officially supported and in the main repository.

• bcmwl-kernel-source (the Broadcom wireless driver) is in restricted, since it is a supported, but proprietary, driver.

• Community written software that is not officially supported (for example, the game supertuxkart) is in the universe repository.

• Packages like ubuntu-restricted-extras (which contains proprietary codecs that allow you to play media files, including flash player) are in the multiverse repository because they are not free and their restrictive licenses prevent inclusion in the default package set.

From Wikipedia:-

Mostly yes, from https://wiki.ubuntu.com/Ubuntu/ForDebianDevelopers

Packages

Most source packages in all Ubuntu components (about 4 in 5 at the time of this writing) are copied unmodified from Debian, but other sources include apt-get.org, REVU, directly from organisations such as Blackdown and WineHQ, software which has been packaged by Ubuntu developers, and packages created specifically for Ubuntu.

In some cases, the same upstream software is packaged separately in Ubuntu and in Debian, though this is to be avoided unless there is a justifiable reason to do so.

Where packages in Debian and Ubuntu have a common heritage, the packages use version numbers which reflect this.

This only refers to source packages - all binary packages are built on launchpad using the current toolchain in Ubuntu