extrusion
[ik-stroo-zhuhn] / ɪkˈstru ʒən /
noun
plural extrusions

1. the act of extruding or the state of being extruded.
2. something that is extruded.

From context, I would expect the latter definition to be what they meant.

Oh, you don't know what "extruded" means either? Don't worry, I got you.

extrude
/ ɪkˈstruːd /
verb

1. (tr) to squeeze or force out

2. (tr) to produce (moulded sections of plastic, metal, etc) by ejection under pressure through a suitably shaped nozzle or die

3. (tr) to chop up or pulverize (an item of food) and re-form it to look like a whole

4. a less common word for protrude

"LLM extrusion" most likely refers to definition 1 or 3, or some synthesis of the two.

Hope that helps!