It's a good point. I responded to the adjacent comment. After glancing at that RFC I'm unclear about the purpose of the UTC offset. Is it simply an error check

It's a good point. I responded to the adjacent comment. After glancing at that RFC I'm unclear about the purpose of the UTC offset. Is it simply an error check to catch the case of a datetime library with outdated timezone information? Otherwise it seems like the library will have all the historical information on hand so it shouldn't have any use for it.