Bing is now testing showing branded side labels next to each search result listing. We saw earlier more basic side labels and before that branded side bars for some search queries. I am also seeing favicons on the side of the snippets. Bing is always very busy testing these things.
This was spotted by Frank Sandtmann on Mastodon and Shameem Adhikarath on Twitter - here are the screenshots they provided that you can click on to enlarge:
I cannot replicate this yet.