Glutton's Jaw - Critical Weapon Specialization?

[Verzen]

What is the critical weapon specialization of this?

[Nefreet]

Glutton's Jaw

Looks like most other unarmed attacks are categorized as Brawling, so I would think it would be the same.

It's also possible it doesn't have one. The section on Unarmed Attacks states they "can belong to a weapon group", which isn't all inclusive.

Hard Tail is another unarmed attack that doesn't list a critical specialization effect.