Two years ago, Google added a “mobile-friendly label” next to the search results to help users identify which web pages will be best for your mobile device. But in those two years, 85% of all pages in the mobile search results have become mobile-friendly.
So, to keep the search results from cluttering up, Google announced on their webmasters blog that they will be removing the tag.
While the label will be removed from the search results, the mobile-friendly criteria as a ranking signal. Google also said that the mobile usability report and mobile-friendly test within Search Console will still be available for use.
Here is a screenshot of how the mobile-friendly label used to look, before it was removed: