Where to buy

https://www.amazon.co.uk/dp/B07MB8Y8SF

Additional board manager: http://drazzy.com/package_drazzy.com_index.json

https://github.com/SpenceKonde/ATTinyCore?tab=readme-ov-file

Random tutorials that got me there

https://startingelectronics.org/tutorials/arduino/digispark/digispark-windows-setup/

https://www.instructables.com/How-to-Setup-DigiSprak-Attiny85-Board/


Sample sketch with LED connected to pin 1 and GND
<code>
void setup() {                
  // Initialize the digital pin as an output
  pinMode(0, OUTPUT);      // LED on Model B
  Serial.begin(9600);

  // if analog input pin 0 is unconnected, random analog
  // noise will cause the call to randomSeed() to generate
  // different seed numbers each time the sketch runs.
  // randomSeed() will then shuffle the random function.
  randomSeed(analogRead(0));
}

void loop() {
  digitalWrite(0, HIGH);   // Turn the LED on
  // delay(random(1500));             // Wait for a second
  delay(2000);
  digitalWrite(0, LOW);    // Turn the LED off
  //delay(random(500));             // Wait for a second
  delay(1000);
}
</code>