This is a simple ticker for the D-Droid ESP8266 which is sold under various guises on ebay and banggood. eg. https://www.banggood.com/Wemos-Nodemcu-Wifi-For-Arduino-And-NodeMCU-ESP8266-0_96-Inch-OLED-Board-p-1154759.html. I used this case https://www.thingiverse.com/thing:2756473
In the Arduino IDE:
Go to File > Preferences and add http://arduino.esp8266.com/stable/package_esp8266com_index.json to the Additional Boards Manager URLs field.
Go to Tools > Board > Boards Manager and add the ESP8266 package. See the attached screengrab for the board setting.