howto for esp8266 in Arduino IDE
From email on 19 May 2019 to RPi group
with reference to my previous comment:
File -> Preferences . Then find 'additional Boards manager URLS'.
Click on the icon at the far right-hand side - like two overlapping pages - a window pops up.
Then click on 'Click for a list of ... ' which will open a git-hub page.
Look in the readme for ESP32...
