The value's kind: the properties it has and how they show. Every value of a kind returns the same instance.
The name of the property to retrieve.
The value as JSON, which its kind makes it again from. A value that holds a resource (a
picture's bytes) names it by the id toResourceId answers, and the file saves the resource;
without toResourceId it names none.
The text shown for this value where nothing renders it: a client with no renderer for the kind, a log, a placeholder. A rich text shows its text; an image a short description.
Display only. What the value reads as to calculation, sorting and the clipboard is toPrimitive.
A value whose kind nobody has registered: it carries its JSON as it was read and reads as nothing, so a workbook that holds one saves it unchanged.
Remarks
Its kind is made from what it holds: named by its JSON's
type, with a property for each entry of its data.