Artist-Release 'booking' relationship "credits a person who was responsible for booking the studio or performance venue where the release was recorded." It is at the same level than other Artist-Release relationship subtypes of 'miscellaneous support', according to the documentation.

In the relationship editor, the items indentation in the type selection menu misleadingly suggests that 'booking' has the four following subtypes: 'art direction', 'design/illustration', 'graphic design', and 'photography' (see the attached screenshot); whereas they should be at the same level of indentation like siblings.