Unknown icon in tray (non removable)

I cannot remove one icon from my tray top menu. I tried to drag it with pressed "Command" key but it has gray crossed circle sign and stays in tray.
When I press this icon it shows "Open Console" but it does not open anything.

It is a green square with white arrow in the bottom part of this icon

I have noticed it appears in my account only. If I open another account it does not have this icon in tray.

Thank you!