Skill-Based ST for Psionic attacks?!

[JulianLW]

Hey, y'all!

I was looking at Generic Universal Eggplant's "Mind Blade" power, here:

https://enragedeggplant.blogspot.com...ind-blade.html.

This feature of the power caught my attention:

It is wielded with the Force Sword skill, but for the purpose of damage use your Mind Blade skill instead of ST....

So I started to try to track down where this skill-based ST rating came from in the rules. Since the Mind Blade is built using the Natural Weapons rules (which may be somewhat problematic for some folks), I looked at Pyramid 3/65, "Natural Weapons," by Ítalo Gomes Gonçalves, where I found this power:

Telekinetic Push: Natural Weapon (Crushing; Cannot Parry, -40%; Cone, 5 yards, +100%; Double Knockback, +20%; Hidden, +20%; Intangible, +50%; No Blunt Trauma, -20%; No Wounding, -50%; Power Modifier, Psychokinesis, -10%; Projected, +50%; Ranged, +100%; Swing-Capable, +20%) [17]. Notes: If you are using GURPS Psionic Powers, damage and range can be based on the psionic skill (instead of ST) as a special effect. 17 points.

So then I looked at GURPS Psionic Powers - and I can't find the source of this "special effect" anywhere. Am I missing it? I think it's pretty cool, but did Gonçalves just make it up?