In addition to having a modern design, the Outlook icon is yellow. That would be a return to form since the Outlook icon was changed from yellow to blue over a decade ago. As far as I can tell ...

You can change your homepage in one of two ways — by either clicking and dragging the webpage URL to the Home icon or accessing ... A white circle with a black border surrounding a chevron ...

Google is now updating the icon so that there are no longer four solid color sections. Instead, red bleeds into yellow, yellow into green, and green into blue. It looks more vibrant and colorful.