Property: Credit as musician
From Broadcast for Schools.co.uk.co.uk
This is a property of type Page.
Property:Credit as composer and Property:Credit as lyricist are stored separately for returning in different sorts of queries.
However composers who weren't directly involved with the schools TV or radio programme ARE stored here in Credit as musician (using Credit type "Music (source)") so they don't get in the way of reporting composers who were directly involved.