setting paths that include .experimental. are intended for settings that may be promoted to "real" settings in the future, or may be removed. When users put these settings in their ~/.lldbinit files, we don't want to emit an error if the setting has gone away. And if the setting has been promoted to a real setting, we want to do the right thing.
The first part of that -- not emitting an error -- did not work correctly. I fixed that, and added tests to check all of these behaviors.