Google is testing showing the overlay feature for its shopping ads, when you click the “view more” both at the top and the bottom. Here are GIFs showing how the overlay either pins itself to the top or pins itself to the bottom.

Here is what I see with the feature at the top:

Saad AK noticed it on the bottom and posted that on Twitter:

He also said he noticed new functionality, specifically “Expand arrows on Search Ads which was opening the Ad in the same window for a better viewing experience & it also had “About this store” feature in it.” I am not sure if those are new or not.

Forum discussion at Twitter.