Google AdSense has introduced favicons to text ads. It is a small graphic that can be used by advertisers to brand their website, may be their company logo. The latest introduction by Google will make ad formats better for website owners, users, and the advertisements appearing on the page.
The AdSense team believes that adding favicons to the ads will make advertisers more recognizable to users, which will in return benefit you as well as the advertisers whose ads are appearing on your website.
You can share your feedback about the new look of text ads on AdSense +page.AdSense Introduces Favicons to Text Ads!,