It&#x27;s multiple, interwoven hierarchies, which you can look at by &quot;seeing&quot; a particular DAG (a subset of the actual graph).<p>You can see this twin representation conceptually as Artist-&gt;Album-&gt;Song and also as Compilation-&gt;Artist-&gt;Song, the latter being a small folder with symlinks to the actual song directly.<p>It&#x27;s really just two different trees.