Jonathan Jones, who is based in the UK, posted on Twitter, that he saw Google overlay a message on top of the search results, saying "A Privacy Reminder From Google."
The query that triggered this for him was [best bank accounts] but I cannot personally replicate this.
When you click on the "review" button, it takes you to this Google page and when you click the read later link, it removes the box.
Typically, you'd see this pop up at the top right of the page, not in the middle as an overlay.
Forum discussion at Twitter.
