Google is testing having the "Show More" button within AI Overviews jump you directly into AI Mode as opposed to loading more of the AI Overview beneath it. This appears to be a test, as I am unable to replicate it.
Here is a recap of what happened in the search forums today...
Google has added a new promotion option to Google Merchant Center. The new option is Google Wallet. Google doesn't detail what this promotion does but it likely lets you promote that you accept Google Wallet for purchases.
Microsoft is telling Bing Search users when it is using history for some of its search features. Bing will show section named "History" and then say what history is knows about your searches.
Google is testing a new, more publisher-friendly version of the AI Overviews for recipe results. The new design has the recipe cards at the top, citations at the bottom and a shorter AI response.
Google is testing using the italic font type for the links in AI Mode. So the links have a bit of a slant to them, compared to the other text in the AI Mode response.