A few days ago, some Edge Insiders started seeing new round icons on Microsoft Edge, such as icons for menus, settings and more data in the UI.
Microsoft today announced that it is gradually releasing new icons supported by the latest version of the language Fluent Design.
Microsoft says there will be two phases of updating the new iconography on the Edge. This first phase will cover the icons in controls such as tabs, address bar, and navigation icons. 
The second will include tools developers and the experience of extensions.
According to Microsoft, the Edge icons have not been updated since 2014 and follow Microsoft Design Language 2 (MDL2). The new icons are created according to Fluent Design guidelines from 2020.
For more details, take a look at publication of the company
