The Moteinos have an LED onboard. But it’s not on D13 as regular Arduinos, instead it’s on D9 (PWM pin, can be faded). I’d like the LED to flash when the bootloader starts and when Moteino is programmed from the Arduino IDE. So I rebuilt Optiboot for this purpose and all future orders for Moteinos will come with this tweaked Optiboot that will make use of the onboard LED when you reprogram it.
This is a video of how I program and test Moteinos before I ship them to you, also showing the updated Optiboot in action: