addInsOf

The add-ins of issueId — the supplements shipped with that release, each one an issue of another publication which a reader entitled to it can also read.

Keyed by issue, not by publication: add-ins belong to a dated release, so two issues of the same title can carry different ones, or none. An issue with no add-ins leaves the block to collapse, like any other empty shelf.

Each cell names the publication its add-in belongs to, which the catalogue side-loads — unlike ofPublications, where every cell is a release of the same title.