"Glen Choo via GitGitGadget" [off-list ref] writes:

From: Glen Choo <redacted>

..so that the callback can use a "struct config_source" parameter
instead of "config_reader.source". "struct config_source" is internal to
config.c, but this refactor is okay because this function has only ever
been (and probably ever will be) used internally by config.c.

Maybe s/this refactor/adding a pointer to a struct defined in a .c into
a public function signature defined in a .h/

So this means that callers cannot instantiate that public function
unless they are in config.c, but I see that it has been appropriately
documented, so it should be fine.

Thanks for this series. Overall I had some minor comments, but things
look good overall.