Google Search is testing a filter button for shopping related query refinement. I personally do not see this but Saad AK posted a screencast of this, showing a filter button at the top left of the search results after searching for [jeans].
When you click on the filter button, you are presented with a ton of shopping related refinements from brand, length, leg style, material, pattern, style, specialty, reviews, nearby, sales, and more.
Here are some screenshots followed by the video cast:
Then when you click on the filter button, a filter section comes up:
Google > Mobile
I saw Filter button in search bar menu links.
It had multiple filters in it:
& Many more.
— Saad AK (@SaadAlikhan1994) June 11, 2022
Forum discussion at Twitter.