You'll need to regenerate your config or copy the new sections from here.

This new stat is displayed at the very top of of the horse stats message, it's a single number that gives an overall score for a horse (50 being average and 100 being perfect stats). You can also disable this stat from being shown at all in config just incase you want people to work it out themselves. Currently this score only applies to normal horses because other variants have different averages which would complicate the formula.