Google started testing expandable overlays for hotel highlight icons last months and they seem to be rolling out now. Now, when you click on any highlight icon in Google hotel listings an overlay is triggered with more details about amenities and different features and you can swipe to see more highlights, expand more photos and reviews, or close the overlay view.
Depending on the highlight Google can either let you know that a particular amenity is a rare find for hotels in the selected area or give it a rating from 1 to 5, which seems to be the average of all user reviews mentioning the highlight.
Also, Google can show relevant photos and reviews (sourced from different sites).
I can replicate this feature on different phones and in different browsers which usually is a very strong indicator of a roll out. This feature is not yet available on desktop.
While Google seems to pick up a lot of information for these highlights from online reviews, checking amenities and attributes within GMB is something hotel marketers can do to make sure their listings are accurate.
Here are more screenshots of the feature for various highlights: