Microsoft is testing showing sitelinks with light gray underlines in the Bing search results.
Normally, the Bing sitelinks don't have any underline at all - but here Bing is testing this.
This was spotted by Sachin Patel who posted this screenshot on X:
This is what I see:
I am not sure if there is enough of a difference here for the average person to notice?
Forum discussion at X.