I think that you have made the right decision. One of the most common and high-impact failure mode is crashing when parsing a leap second that is represented a

I think that you have made the right decision. One of the most common and high-impact failure mode is crashing when parsing a leap second that is represented as "23:59:60". Jiff is able to parse leap seconds, and beyond that, I doubt that there are many scenarios where you care about leap seconds but not enough to use a library that supports them.