Galleon 2.x is the version branch which is going to be exposed as a supported external tool for provisioning, updates and patching.
The main difference to Galleon 1.x that it brings into WildFly build process is it is based on different format for expressing feature-pack locations than Maven coordinates and uses a resolution mechanism to resolve feature-pack artifacts, which is the base for version updates and patches discovery.
There is still a way to provide Maven coordinates for feature-packs and avoid going through the default feature-pack resolution mechanism.
Another feature it brings in and which appears in wildfly feature-pack configs is proper transitive dependency customizations.

The equivalent change for WFLY is WFLY-10703