Does a "configuration language" specifically incorporate features for "overlaid" or "unified from parts" configuration? Much like layered dockerfiles, mature c

Does a "configuration language" specifically incorporate features for "overlaid" or "unified from parts" configuration? Much like layered dockerfiles, mature configuration often comes from several places: env vars, configuration appropriate for checkin to git (no secrets), secrets configuration, and of course the old environment-specific configuration. All of that merges to "The Configuration". Also, these seem close to templating languages. I've done this several times with a "stacked map" implementation (much like the JSP key lookups went through page / session / application scopes, or even more convoluted for Spring Webflow.