Bing Experiments With Open Button for Displaying Sitelinks in Search Results
TLDR
Bing is testing an expandable sitelinks interface with an "Open" button that toggles a side panel showing domain links, a departure from traditional sitelinks display.
Optimixed Overview
Optimixed's original report on this story.
Microsoft Bing is experimenting with a new way to display sitelinks by introducing an "Open" button that reveals sitelinks in a side panel when clicked, rather than showing them inline below the snippet. Per SERoundtable, this interface is unusually different from how sitelinks appear on Bing and Google today, and users can close the panel or click through to the displayed links as needed.