The NotesJSON* classes were introduced with Domino V 10.0.1. In V 11 a few methods were added but the documentation is still as poor as on day one.
Most prominent example:
NotesJSONElement.Type property just says this:
Constant in JSON element that indicates the type of value represented by the value property
And that's it: no hints as to which type is bound to which value, just named constants in alphabetical order (no: Jsonelem_type_array is NOT representing value = 1, that would be Jsonelem_type_object...).
Retrieves a NotesJSONElement using JSON Pointer syntax to identify the element
etc. No hint in regards to when to use a pointer as opposed to use GetElementByName
Of course I can look that up somewhere in the web. Still this is extremley poor. Compare it to other LotusScript classes and their methods and you know what I mean.
Also: unlike other classes / methods / properties there's no hinting as to which Designer version introduced those classes / methods.
For a much more positive example see e.g.
Represents the replication settings for a pair of servers in a database.
This class is new with Release 6.
NotesJSON* classes are just an example; I could come up with others of classes/methods/properties added lately.
Please invest a couple of days to polish up Designer documentation to be like it used to be in the past!