High end subscription based music organizing and playback service. It’s for your digital files and also incorporates Tidal and Qobuz if you have subscriptions to those. Kind of expensive so not for casual music fans. It basically interconnects everything to do with your music files and has a lot of playback features. Can be fun to play with for a few months even if you don’t subscribe. It now has remote playback which was recently added. Info on the new version here: https://www.youtube.com/c/roonlabs