https://github.com/esp8266/Arduino
installed from library manager
https://github.com/adafruit/DHT-sensor-library
Examples include both a "standalone" DHT example and one that works along with the Adafruit Unified Sensor Library. A Unified sensor library is required even if using the standalone version.
Used the "standalone" version for reading the DHT22 sensor.
dependency of Adafruit DHT-sensor-library, has to be installed to compile sucessfully although not really used for the "standalone" DHT library.
https://github.com/adafruit/Adafruit_Sensor
AP with captive portal for initial (WiFi-) configuration.
Used with modification - added #define WIFI_HTM_PROGMEM to PersWiFiManager.cpp (turns off SPIFFS usage and stores HTML page to PROGMEM to simplify firmware upload)
https://github.com/r-downing/PersWiFiManager
MQTT client for Arduino
https://github.com/knolleary/pubsubclient
https://pubsubclient.knolleary.net/
from v0.4.0:
LiquidCrystal_I2C v1.1.3 from here:
https://github.com/johnrickman/LiquidCrystal_I2C/releases
pre v0.4.0: commit e3701fb
2017-03-09 from here:
https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library
Button handling library with callbacks on press, release, hold, hold-repeat.
PushButton.h extends Button.h.
https://github.com/r89m/PushButton
https://github.com/r89m/Button
used by r89m Button/PushButton.
https://github.com/thomasfredericks/Bounce2
for experimental Web console
https://github.com/Links2004/arduinoWebSockets