Library for runtime application configuration—interested?

Agreed. This technique is required for how I think I’ll be implementing test helpers, in a “block only” format that always tears down its own pdict overrides afterwards, but if I expose it as a library feature for production usage, it’d probably be in something like an Advance Usaged section, with ample caveats, such as you REALLY should ensure the process in question lives in a receive loop and checks its mailbox for cache-busting events from the library.