Google has dropped showing the AMP label or icon in the mobile search results. I personally cannot trigger it for any of my searches anymore. And no, it does not seem to have been replaced with the page experience label either.

Here is a screenshot of a page that normally would have a gray AMP lightening bolt icon but no longer does:

Here is a GIF showing the top stories carousel not showing any AMP icons:

Last month we saw non-AMP pages showing up in these areas and now we are seeing even AMP pages (when you click on the results above, you are taken to the AMP version) not show the AMP label.

Others are seeing this as well:

Forum discussion at Twitter.