Good point, @geigerzaehler. This is residual from back before we had AlbumMatch and TrackMatch structures. When it was introduced in 08b539a80efd9c7ebf9954372b6dda1ef9e72977, we actually changed the `items` field to include Nones in the case of partial matches. Now, of course, partial matches are indicated with the AlbumMatch's mapping.

I'll take this check out (and one other).