It may be tempting, for the sake of brevity, to put complicated initialization details into a standalone script and merely add a RUN command in the Dockerfile. However, this causes the resulting Dockerfile to be overly opaque

consider a situation where the branches of the oneOf are separate schemas owned by other entities (and therefore impossible to refactor without forking), which are intended to provide an opaque validation interface (and therefore may change internal details without warning, but without changing the desired validation outcome) and are included by $ref

One can say this code is opaque compared to the previous example but keep in mind that in real code it often happens to call methods returning Maybe values.

Axiom: Opacity of URIs The only thing you can use an identifier for is to refer to an object. When you are not dereferencing, you should not look at the contents of the URI string to gain other information.