The title that iTunes uses when it sorts media items by title.
- macOS 10.13+
If, for example, the title of a media item is The Sound Of Music and sort title is Sound Of Music, when iTunes sorts media items by title, this media item would be grouped with other media items whose titles begin with "S".
If no sort title is specified, this property is nil and iTunes uses the value of the
title property when it sorts media items.