There are a few things being confused because people are having to learn/re-learn/re-discover basic computer science classes, but both formal specifications and informal specifications - such as pseudocode (I balk imagining how many AI users might not know this term), or natural language documentation - are all forms of abstraction. Programming languages and underlying models of computation all enable varying degrees of hiding details or emphasizing important ideas/information. Human thought and language, and mathematics, are already examples of abstraction in general. LLMs thus also purport to provide a (via computational model alternative to Turing machines) higher kind of abstraction, the debate is whether it is a good one, if its hallucinations make it unreliable, etc.