Bukkit

Healthbar duration

This determines how long healthbars stay on screen during combat.

Healthbar durations are set under "duration". This duration is in ticks (20 per second).

With a duration set to 60, healthbars disappear after 3 seconds of not atacking entities.

Custom healthbars per entity type

Custom styles are applied under "styles"

Here's an exaggerated example:

....
styles:
  Zombie:
    color: PURPLE
  Skeleton:
    color: WHITE
    style: SEGMENTED_10
  Player:
    color: BLUE
  Animals:
    color: GREEN
  Sheep:
    color: WHITE
  Monster:
    style: SEGMENTED_6

Styles are determined from top to bottom, when the attacked entity matches it will pick that style.

Because of this, "Sheep" will never get matched in the example above, since it's already matched as part of "Animals".

Keep this in mind as you add your custom styles. Keep broader matches in the bottom.

The type of monster can be any subclass of "LivingEntity", but here's a full list of options (as of 1.12.1):

AbstractHorse, Ageable, Ambient, Animals, ArmorStand, Bat, Blaze, CaveSpider, ChestedHorse, Chicken, ComplexLivingEntity, Cow, Creature, Creeper, Donkey, ElderGuardian, EnderDragon, Enderman, Endermite, Evoker, Flying, Ghast, Giant, Golem, Guardian, Horse, HumanEntity, Husk, Illager, Illusioner, IronGolem, Llama, MagmaCube, Monster, Mule, MushroomCow, NPC, Ocelot, Parrot, Pig, PigZombie, Player, PolarBear, Rabbit, Sheep, Shulker, Silverfish, Skeleton, SkeletonHorse, Slime, Snowman, Spellcaster, Spider, Squid, Stray, Vex, Villager, Vindicator, WaterMob, Witch, Wither, WitherSkeleton, Wolf, Zombie, ZombieHorse, ZombieVillager

Possible bar styles:

SOLID, SEGMENTED_6, SEGMENTED_10, SEGMENTED_12, SEGMENTED_20

Possible bar colors:

PINK, BLUE, RED, GREEN, YELLOW, PURPLE, WHITE