Nodemcu or any module pins_arduino.h

Esp8266 modules, Node MCU type, are a piggyback module on top of a module.
The topmost module pin numbering not the same as the main module. And I have
never seen the piggyback, if its labeled, showing on it. Must be under its metal cover.

Further I have main modules both with labeling, and without.

Cap that with the symbolic names have a pinout equivalent when compiled
into actual code. So when debugging one needs to know that.

So we have two modules, each with their own pinout, and symbols with a numeric value when code generated.

Regards, Dana.