Trait: Heavy⚙️
Items that are heavy have extra./added weight to them, making them unwieldy to those who do not have the strength to lift them (literally). As such, Heavy items (such as weapons and armor) will have their extra weight included as a stat, while the trait itself adds a requirement that, itself, can lead to interactions with other features and talents. That said, not every Heavy item weighs a lot. It’s a matter of use. Or something.
There is no other penalty for Smaller creatures wIelding Heavy Weapons, aside from Bulk.
Trait Mechanic⚙️
Weapons and Armor with the Heavy Trait require a minimum Strength attribute to be wielded, along with being trained in the item’s relevant proficiency (Martial weapons, Medium or Heavy Armor, etc). The minimum requirement will be listed in parenthesis next to the keyword, even if the Strength requirement is “+0”.
Once again, there is no other penalty for Smaller creatures weilding Heavy Weapons, aside from Bulk.