Abilities as Techniques on page 33 pf Pyramid 83 (Alternate GURPS 4) is part of Possessions Under Control
It uses Powers 173 rules for Using Abilities at Default:
- Eavesdropping is Mind Reading
- Inquisition is Mind Probe
- Mental Contact is Telecommunication
- Steal Possession is Leech
- Terrorize is Terror
It does not however use the Powers rules for needing to spend FP and make a skill check just to temporarily get the aiblity - they are treated as permanent possibilities by doing penalized skill rolls for possession instead.
This is more derived from the Psionic Powers rules on page 8-10 for Psi Techniques. This is normally for adding enhancements instead of different advantages, however the idea of enhancements adding new advantages is already present for possession under the Transformative enhancement.
There are possibly examples of "advantages as enhancements" via Temporary Enhancements in GURPS Psionic Powers too.