Well, for more background info I am not suggesting this purely whimsically, I went through a debugging session a month or two ago where I was trying to understand message acceptance. After an hour, I figured out "Oh, stupid, it's not that this user has default processing! No. They are using defaults. Quite different."
Not sure what an analogy is. A car dealership which has two red cars, and distinguishing them using the terms "red automobile" versus "red car" to keep them separate.
Even now, I think "You can choose either default processing, or default processing, but don't get those mixed up."
About implying "modifiable",
we often use the terms "settings" or "configuration" without explicitly adding the adjective "modifiable". Many variables and configurations in technology are modifiable. That does not always need to be stated outright. If "processing" occurs, it does not imply unmodifiable.
The terminology appears in drop-down lists within Hyperkitty, so more than only docs.