Three microphones?

[N4Newbie]

Come to think of it, the specs state, "3 microphones (2 front, 1 rear) with noise cancellation"

Okay, one of them is on the back near the two laser-focusing ports, and one is (presumably) behind the dummy bottom-facing speaker grill. Where is the third? Under the earpiece grill??

 

[Rocky5000100]

Yup, see step 7
https://www.ifixit.com/Teardown/Google+Pixel+XL+Teardown/71237