Booking.com says that for listings that do not have reviews yet, they will fetch reviews from "other travel websites" but they do not mention which ones.
Which websites are they talking about? The reason I am curious is because on the listing in the screenshot they say they have 23 guest reviews from other websites, however, when I tried finding the listing on other websites I could find no other ones, except for booking.com itself.
So I am wondering where they got the reviews from, and whether they can be trusted. I am hesitant to just take booking.com at their word that they come from a trustworthy source (not saying they are not, but it would be nice to. know where they came from.)