Three WLED SW forks are particularly important:
1. The Original: Aircoookie WLED. This is the original WLED SW. Up to version 0.13.3 there was no way to make Sound Reactive WLED using this version. Beginning with version 0.14.0 a so-called Audio Reactive Usermod is available.
2. (obsolete) Sound Reactive WLED: this branch was created a few years ago and implements the so-called Sound Reactive WLED. With a microphone or line-in input it is possible to have the LEDs react to the music (or other noises) and then light up with music beats, for example. This branch must now be considered obsolete. You should use the original one with Audio Reactive Usermod.
3. MoonModules WLED: this branch is a "playground" created by some WLED developers, mainly to try out new functions or to test experimental changes of existing code.
With this WLED installer you can install and try out every version.