Official JSON Schema for npm audit –json Output?

I’m looking for an officially documented JSON schema that defines the structure of the output from the npm audit --json command. While I understand that the output includes keys like actions, advisories, metadata, etc., I couldn’t find a formal schema in the npm documentation or repository.

Is there an official JSON schema or response type definition available? If not, is the CLI source code the only reference for the expected structure? Is the output structure stable, or can it change between versions?