The term data model can refer to two distinct but closely related concepts

unevaluatedProperties is similar to additionalProperties in that it has a single subschema, and it applies that subschema to instance properties that are not a member of some set.

Epics, issues, requirements, and others all have similar but just subtle enough differences in common interactions that the user needs to hold a complicated mental model of how they each behave.

An Euler diagram (/ˈɔɪlər/, OY-lər) is a diagrammatic means of representing sets and their relationships. They are particularly useful for explaining complex hierarchies and overlapping definitions. They are similar to another set diagramming technique, Venn diagrams. Unlike Venn diagrams, which show all possible relations between different sets, the Euler diagram shows only relevant relationships.

A ponyfill is almost the same as a polyfill, but not quite. Instead of patching functionality for older browsers, a ponyfill provides that functionality as a standalone module you can use.