Note that full support for creating Arduino IDE 2.x extensions equivalent to the Arduino IDE 1.x Tools was completed by adding the previously missing capability for extensions to get the Arduino-specific state information from the IDE in...
The icon appears when the user has selected a board that is different from the board the port was identified as.
In the example of your screenshot, port "usb:0/140000/0/2" was identified as a "Teensy 4.1" board, but you have selected the "Teensy...