Building
You do NOT have to build the game engine to play or create games. Building is only required for Linux distribution maintainers or those having a special use case.
GIT Branches
The master branch is the current development branch with the most recent work. It is potentially unstable and should be only used by developers working on bleeding edge software build against the upcoming release.
The stable branch is the stable branch pointing to the latest release. This branch is for public use by distribution builders and developers working on software to work with the latest stable release.
All other branches are internal feature development and platform support branches not intended for public use. If you want to work on these branches please get in contact with the development team first.