It seems to be open source: https://github.com/AudiusProject/audius-client
Mmm. Basically they’re a soundcloud/spotify platform based in a blockchain protocol in terms of monetization, that’s it. Only their client (Another React app) and protocol (ethereum) are open source (Apache License 2.0) the rest is the same: Another privative/centralized music platform with DRM.
At the moment the only real federated/decentralized music platform is Funkwhale. Or Jamendo which is centralized but all its content is under Libre/Free copyright licenses like Creative Commons.