What is Live Source Code Access

In Unreal Engine 4.1 update preview, i read they are bringing ‘live’ source code access feature. It sounds something cool so i want to know what exactly is that?

We’re planning to bring you guys source code changes right as they happen, or as shortly as possible after the code is submitted to our main repository. It will probably take us a few weeks to get it the process all sorted out, but in the meantime you can already access the full source on GitHub, including a work-in-progress build of the upcoming 4.1 release.

–Mike

So our build will be updated with the updated source code? Or the GitHUB will be updated as it happens/changes.

GitHub master branch will be updated as soon as some changes are available.
Basically something for adventurous people, who like to test newest features.