Microsoft seems to be testing a more fully AI-powered search engine, which may be named Copilot Search. Copilot is the name of Microsoft's AI features, formerly known as Bing Chat.
Mayank Parmar spotted this test and wrote about it on Windows Latest. If you want to try it yourself, you can by going to bing.com/copilotsearch?q=windows - you can replace the query "windows" with whatever you want.
As you can see, it says "This summary was generated by AI from multiple online sources. Learn more about Bing search results here" at the top of the page.
Here is a screenshot:
Here is a GIF of this in action shared by Mayank (click to enlarge it):
Here is a static image:
This looks a lot different from both Bing Search, the Bing Generative Search Experience and Copilot.
Forum discussion at X.