Validation of M1s reports built-ins not being declared

[dslmeinte]

The error message is: LanguageUnknown: Node uses language { language = LionCore-builtins, version = 2023.1 } which is not declared in used languages at $.node[???].property[???].

But according to the relevant section of the specification this is only an error if the serialization chunk represents an M2.

[joswarmer]

The referred Note states that this is an error for a chunk rep[resenting an M2 model. It does not state that it isn't an error for a non-M2 model. So the question is what was the intention of the note:

1. State that this is only mandatory for M2 models
2. State that this mandatory even for M2 models (like everywhere else)

I think it is 2.