Badges update automatically and link to the resource pack page on MineUniverse.
It's a resource pack that refreshes the appearance of zombies with a wide variety of models and textures. It includes random variants and unique designs tailored to each biome and altitude level.

This package uses an OptiFine feature called CEM (Custom Entity Model) for its 3D functionality, so it is recommended.
[EMF] and ETFs share the same feature, but it is required for it to work.