Jeff King [off-list ref] writes:

OK. I don't have a strong opinion. Are you OK with core.commentString as
a strict synonym (so last-one-wins and either name overwrites previous)?
Or do you want an override (i.e., commentString always overrides
commentChar, regardless of order). I think it's mostly academic, and the
strict synonym version is much easier to implement.

When I wrote it, I meant "String is a successor of Char, if both
exists that is used regardless of the order", but either is OK.
Older versions of Git would not understand the "String" version, so
it matters only to those who uses mixed versions of Git and they can
control the last-one-wins in their configuration file, I would
guess.

Thanks.