A few days ago, some Edge Insiders started seeing new round icons on Microsoft Edge, like icons for menus, on settings and other elements in the UI.
Microsoft announced today that it is gradually rolling out new icons supported by its latest version languageς Fluent Design.
Microsoft says there will be two phases informationof the new iconography in Edge. This first phase will cover icons on controls such as tabs, address bar and navigation icons. 
The second will include developer tools 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
