Valve has made a major change to how game soundtracks are handled on Steam.
For the longest time, Steam considered game soundtracks to be DLC. This necessitated tying soundtracks to games, meaning you couldn't just buy the music on its own.
Valve has now announced that going forward, Steam will recognise soundtracks as their own thing. By creating a specific app type in Steam's database, customers can now download, listen to and even purchase game soundtrack without having to own the game in question.
Steam's new library interface has also been updated to keep track of all your owned albums separate from games, and you no longer have to navigate to each game's directory to listen to these tracks.
Valve is also making it possible for developers to upload rips of varying qualities to Steam's servers, which in turn allows customers to download the format/quality they need.
Everything from the common MP3 to the bigger, lossless formats like FLAC and WAV are supported. If you opt in to receive the higher-quality formats, Steam will automatically download them when available.
Another side effect of the new system is that soundtracks can now be sold on Steam even if the game in question isn't itself available on Steam.