Why Is Microsoft Edge Adding Its Own UI to Websites?

I’ll readily admit that I’m not a regular user of Microsoft Edge. The browser works just fine. But I’ve been a diehard fan of Firefox for years. The Chromium-based successor to Internet Explorer never gave me a compelling reason to switch.
Thus, I was greatly surprised by a recent question from a client. They wondered why, when hovering over an image on their website, a small icon appeared. Was this a new feature?
Usually, these types of issues are caused by an overzealous brow