What it is
Triethoxycaprylylsilane is a silicone.
What it does
Triethoxycaprylylsilane is an emulsifier that prevents the oily and liquid parts of a formula from separating.
It is also a binding agent. That means that it can bind pigments to form a stable coating. It allows pigments to disperse well on the skin too, ensuring an even coverage.
Triethoxycaprylylsilane is generally considered to be safe.