If you boil this back to the simplest terms:
What is an official repository and an unofficial one (Local Repository), including the ones created outside of Launchpad.
An official repository is one published as part of Ubuntu, managed by Canonical and Ubuntu MOTUs.
They currently consist of main, restricted, universe, multiverse, partner, extras and some exist in multiple "states" (-proposed, -updates, -backports, etc).
The repo names might change in time but the point is that these are .
On mirrors: The contents (MD5 hashes of files, etc) of the repository are signed with the Ubuntu key so even if you're pulling the official files from a non-official mirror, you can be fairly certain that they are the original files.
How do repositories created outside of Launchpad compare to the ones found inside of it in terms of first, security, followed by any other features that both offer.
You can't implicitly compare security levels between a Launchpad PPA and another non-official repo hosted elsewhere. It all boils down to how much you trust the person running the repo.
The difference is with a Launchpad PPA, you can see the person who is packaging things. Most times you can see the source. In other repos (eg: dl.google.com or repo.steampowered.com) you likely know neither.
Trust is an odd thing.
Feature-wise a repo is just a particular structure of directories and files, hosted on the web. The only special features I've ever seen are authentication to allow only people who have purchased software to download it but this very basic web server security and hardly special :)
How do official software repositories differ from the ones created by 3rd party PPAs in Launchpad or outside of it.
This is perhaps the biggest of the questions and it's probably best answered (if indirectly) by another question: How to get my software into Ubuntu?
Official repo software is supposed to have a development process behind it. Levels of testing that ensure quality and an amount of peer review. PPA maintainers can encourage this sort of process but it's not something you can assume. Some are better than others.
The restricted archive may contain only hardware drivers, not application software. It comes as a compromise in recognition that potential Ubuntu users could not use Ubuntu at all without it. Source: Ubuntu Policy Manual section 2.2.2.
The Canonical partner repository is not part of Ubuntu. It contains anything that Canonical thinks might be useful to Ubuntu users that is not Free Software. This includes application software.
So: restricted is a compromise in Ubuntu to make hardware work, and is restricted to just this. Canonical's partner repository is not part of Ubuntu, but may contain a wider range of non-free software.
Best Answer
Most of Ubuntu is free software (meaning not just that you don't have to pay for it, but also that you can distribute it, study its source, and modify it).
However Ubuntu also includes a small amount of non-free software, in separate components:
restricted(non-free, supported) andmultiverse(non-free, not supported). These are programs that may be distributed over the Internet at no charge, but have restrictions that make them non-free. A prime example is drivers for devices which do not have fully-featured free drivers.You can tell a package is non-free because it's from the
restrictedormultiverserepository. In Synaptic, check the “Section” in the ”Common” tab of the package properties. Exactly what restrictions are on the package has to be determined on a case-by-case basis. Most can be used and redistributed by anyone, but modifications are not allowed and the source code may not be available. A few, such asrar, have restrictions even on use. Once the package is installed, you can always find its license in/usr/share/doc/$packagename/copyright. Onpackages.ubuntu.com, check the “Copyright File” link in the right-hand column.