Users often need to modify the Environment PropertySources but they basically have to guess the best slot to insert a new PropertySource to give it the correct priority. We document the priorities of the "standard" property sources, but we don't provide a way to insert custom properties at specific points in that order. Often a user wants to just add a single k-v pair with "high but not highest" priority, or "low but not lowest", something like that.

Comment From: philwebb

I think we should close this one for now and see how the new ConfigData import support works out. We can reopen it if imports aren't working for a specific use-case.