I was never involved with beta testing Oreo.
I posted the build number, and asked kjharrison about his build number, because we're both using Project Fi. We both received the OPR6.170623.011 build for our Pixel XL phones. Of note is that the information provided for that particular OTA on the Google developer's page does not include Project Fi. Since
Project Fi isn't currently listed, I thought it might be a good idea to provide the build number here just in case someone was trying to determine the correct OTA to download for a Pixel XL on Project Fi.