Library configuration file: Rename default parameters/values in config files to fallback if that is what they are

Whatever they are -- make this explicit in the configuration file property name.

Original question:
Do (any of) these take precedence over the value in the holdings mapping file?

Start by locating the configuration files and the code that reads their parameters alongside the holdings mapping file. Determine whether the values are defaults or fallbacks and whether they take precedence; done means the property names explicitly describe that behavior and the related configuration handling remains consistent.

Written by the indexing model from the issue text.