https://en.wikipedia.org/wiki/GlTF
(note Wikipedia capitalizes it weirdly in the URL but in the page title it is correct)
I just assumed - you know, WebGL, OpenGL. I've even bloody implemented support for it in an app whilst calling it the wrong thing!
I need a sit down and a strong cup of tea...
EDIT - Phew. It is GLTF - in my blind panic I thought it was actualy an "I"
(I don't care how they tell me to capitalize it - that's not something I particularly care about conforming to)