ESP-M3
NOTICE!!!: In the SZDoIT documentation for this module (What you see below as the pinout & user manual...) pin 3 of the module is shown as GPIO13. This is NOT correct. After it was brought to my attention recently (Thanks Ronald), I've done some digging & testing. Even my oldest M3 modules, purchased directly from SZDoIT, have GPIO12 broken out on pin3.
Made by Shenzhen DOIT
Resources
Notes
There is some confusion, ATM, about pin 3 of this module. All of the documentation from Shenzen DoIT shows this pin as GPIO13 of the ESP chip. Some actual modules have it listed on the silkscreen as GPIO12.
Further testing and research will be needed to prove which it actually is.
(hhhmmm... this actually explains the error in my ESP-M3 Everything! board. testing may be quicker than expected.)