"minecraft:wearable" overrides the "minecraft:max_stack_size" component to 1. Makes it difficult to replicate the features of stackable blocks like the skulls, heads, and carved pumpkin.

Note: Holiday Creator Features are required for "minecraft:wearable" (in format versions before 1.20.20)

Step to Reproduce
Download the included pack
Create a new world
Apply the pack
Enter the world
Observe the item "sci:wearable_stackable_item"'s inability to stack