Thank you, I had found that - but not only is that not documentation but even groveling in this code is insufficient: I have config entries, apparently honored, that are not in this source file, including: confirmed_only, fiat_address, show_{addresses,console,utxo}_tab, and many more.
The link above is where the config file is created and read. There are other places where some additional keys are being set in the "config object" which can then be written to disk or read from it later. For example there are a bunch of them including your examples here in
exchange_rate.py file.