Thank you for the review, Per.

I pushed the requested changes. Please review.

I have a few questions and remarks:

• I do not have a classic Nano board; hence I could not reproduce the behavior with an attached board.
• I mocked the board list --watch format json response of the CLI based on your board list output, and it works like this in IDE2 from the PR:
  Screen Shot 2023年01月09日 at 08 58 05
• How can any client of the CLI distinguish between serial and native serial ports:

{
 "port": {
 "address": "/dev/ttyUSB0",
 "label": "/dev/ttyUSB0",
 "protocol": "serial",
 "protocol_label": "Serial Port (USB)",
 "properties": {
 "pid": "0x6001",
 "serialNumber": "AB0P8H9K",
 "vid": "0x0403"
 }
 }
 }

 {
 "port": {
 "address": "/dev/ttyS4",
 "label": "/dev/ttyS4",
 "protocol": "serial",
 "protocol_label": "Serial Port"
 }
 }

• Currently, IDE2 shows an unknown board for a port if the protocol is 'serial' and the matching_boards is not empty or 'vid' and 'pid' is available from the port#properties. Is this the correct approach?
• For the unidentified board, the SN is available: AB0P8H9K. Is this correct to show: "Upload any sketch to obtain it."? Thanks

I have a few questions

• How can any client of the CLI distinguish between serial and native serial ports:
• Is this correct to show: "Upload any sketch to obtain it."?

IDE2 will consider a port a non-serial if:

• The port protocol is 'serial', AND
• The VID+PID is available from port#properties

From @cmaglie:

• before USB, the Serial ports were embedded in the PC. You'll get COM1 and COM2 usually, and you connected them using a 9 pin D-SUB connector this is what the IDE Java calls "native" port, because it's something that is embedded in the PC. It doesn't have any USB VID/PID, so nothing can be told about what you connect to that port
  image (3)
• so fact 1. if you don't have VID/PID than it's a "native" port
• after some times the USB standard got traction and the old serial ports have been replaced by USB-2-serial converters: you had these cables where one side was USB and the other was 9-pin D-SUB. Actually the USB connection was converted to Serial, but in this case the USB VID/PID are fixed, and are those of the chip mounted on the cable. This is the case where that Per calls "unidentified". you have VID/PID but it's the VID/PID of the "converter"
• finally, we got the modern microcontrollers that have direct USB connection, so they can "emulate" an USB-2-serial cable... in this case each microcontoller can send arbitrary VID/PID, because there is no more the real convert cable, it's emulated, so each board can have his unique VID/PID. This is what Per calls "identified" port.

Could you please take another look, Per?