But the LLM won't interpret it formally; it doesn't know the semantics of any of the programming languages it can generate code for, it just "knows" that certai

But the LLM won't interpret it formally; it doesn't know the semantics of any of the programming languages it can generate code for, it just "knows" that certain patterns occur more or less frequently. You can prompt it with invalid code and it will still sometimes give you a meaningful response.