The email in the docs is a reseller. I have already contacted them and know, and I actually found and have spoken to the developer.
The 5V+10R is an optional 5V power input to the module that was added to allow for users of Raspberry Pi to power from GPIO. It provides a simple RC filter on the PCB which is what the 10R refers to.
The diagram is not a real schematic so is not clear, the RFID module takes 5V-9V so what voltage is the battery is outputting? You need a DC-DC step down buck converter from the battery pack to ESP32 for 3.3V output.