for people who wan't the nostalgic feeling of osu!Stable once osu!Lazer gets released.
you'll need prior knowledge in C# and .NET 5 and osu!Framework if you want to develop on Qsor!
If you're a not a developer, you can simply go over to the releases and grab the latest release.
but if you're one, there you go:
:~$ git clone https://github.com/mempler/qsor.git
:~$ cd qsor
:~$ dotnet run Qsor.Desktop -c Release
Qsor's code is licensed under the MIT licence. Please see the licence file for more information. tl;dr you can do whatever you want as long as you include the original copyright and license notice in any copy of the software/source.