INTP:
What kind of LEDs are on the Arduino boards? Indicator ones/ onboard pin13 one.Is there a special term for them other than SMD LED? (Searching for that turned up all shapes and sizes)
What "size" or "model" is used to refer to the ones on the Arduinos?
The size is easy to measure with a caliper guage, most SMT components come in a standard set of sizes,
but there are always exceptions. There are literally 1000's of devices out there from dozens of manufacturers,
there is not enough room for markings on an SMT LED so you can't actually tell what part it actually is,
just guess from the size, colour and brightness.