> These values are part of a configuration format, meaning they are already part of an external API. Being able to change the name of these keys seems like a weak argument considering that changing the name of these keys is a breaking change that should only be done in the most extreme cases.

Good point there. The changes I made then are technically breaking changes since 3 of the keys changed names. We should probably discuss this a little more to see how we can prevent breaks but still  move forward to adopting the new spec.