Bing seems to be testing added “learn more” cards under the knowledge panel within the search results. The learn more cards are in a carousel format that you can slide through to learn more about the topic from third-party websites.

Here is a screenshot of this from Shameem Adhikarath on X (click to enlarge):

Shameem shared more screenshots and before and after shots in these posts:

here is the previous version pic.twitter.com/1LFPgyEWTI

— Shameem Adhikarath (@shemiadhikarath) September 21, 2023

Again, I cannot replicate this.

Forum discussion at X.