This may have made things complicated.
Instead of just packages, now there are two types of packages: a Package, and a Related. To accomodate this taxonomy, both a Package and a Related are Collections, thus, the name of this plugin is now dfm-wp-collection. Shoutout Dan Petty who suggested there would be a use for non-package-type in-article lists. To be clear: A Related is just a list of recent articles that have a particular tag. A Package works the same, but it's more intentional.