AIUI, some systems keep the “default” versions of their configs in /usr/share/<thing>: the apps they configure look first in /etc/<thing> for local overrides, and fall back to /usr/share/<thing> if it isn’t found. I think some even layer the two, such that a partial file in /etc/<thing> gets backstopped by the default version of the file in /usr/share/<thing>.
FWIW, I’ve been building “framework-y” things for a long time now: the idea that a given configuration should be overridden by another partial configuration is almost as comforting as mac-and-cheese (and no, I am under no illusions that my perception here is “normal”).