I tried Adobe Edge Web Font on my website and I discovered that they use a 1x1 beacon called p.gif. What's the purpose of this web beacon?
A solution is to write "img-src 'self' data:" into the Header CSP. data: is for Safari that doesn't show audio controls otherwise.
It's a means of tracking your users. You can block it by using a CSP rule that doesn't include their domain for images. Use report-uri.com to help you configure an appropriate CSP header.