What is the circular icon with double arrows in the lower-right corner of the Windows 11 desktop?

An unknown icon has appeared in the bottom-right corner of the taskbar (near the system tray). It looks like a solid dot with two arrows beside it (possibly pointing in the same or opposite directions). Clicking the icon produces no response or pop-up window. However, when you click the ‘Show Desktop’ button on the taskbar, the icon disappears. It reappears once any application window is opened. Please explain the meaning of the icon, its origin, and how to remove it.