WWDC2016

• Introducing Swift Playgrounds
  https://developer.apple.com/videos/play/wwdc2018/413

WWDC2017

• Teaching with Swift Playgrounds
  https://developer.apple.com/videos/play/wwdc2017/416/

• What’s New in Swift Playgrounds
  https://developer.apple.com/videos/play/wwdc2017/408

• Localizing Content for Swift Playgrounds
  https://developer.apple.com/videos/play/wwdc2017/410

WWDC2018

• Create Your Own Swift Playgrounds Subscription
  https://developer.apple.com/videos/play/wwdc2018/413

• Getting the Most out of Playgrounds in Xcode
  https://developer.apple.com/videos/play/wwdc2018/402

• Create Your Own Swift Playgrounds Subscription
  https://developer.apple.com/videos/play/wwdc2018/413

• XCPlayground Module Reference

https://developer.apple.com/library/archive/documentation/Swift/Reference/Playground_Ref/Chapters/XCPlayground.html#//apple_ref/doc/uid/TP40014789
https://developer.apple.com/library/archive/documentation/Miscellaneous/Reference/XCPlaygroundModuleRef/XCPlayground.html#//apple_ref/doc/uid/TP40016564