These are the example Arduino sketches built in to the Arduino IDE.
They were originally hosted at https://github.com/arduino/Arduino/tree/master/build/shared
For more information about these examples please visit their tutorials at
https://www.arduino.cc/en/Tutorial/BuiltInExamples