Vanilla default attribute. Corresponds to the chance of blocking the knockback of a knockback source (explosion, creeper...). Value is between 0 and 1. 1 is 100%, 0.3 is 30%... etc.
Don't forget to add #knockback-resistance# to the /language/lore-format.yml file if you want to display this stat on your items.
/mi load <type> <id> now features skull texture support!