If I fetch from the texCoord "0, 0", do I fetch from the center of the top-leftmost texel?

Question

What happens when I fetch (via texture()) from the texCoord "0, 0"? I have 2 hypotheses.

1. I fetch from the center of the top-leftmost texel
2. I fetch half a texel to the left and top of the top-leftmost texel. The results depend on the wrapping mode.

Which one is true?

It's surprisingly hard to find info on that.

I found this answer from which I can deduce that "2." is true. But the answerer there gives no reference.