Does the Rogue’s Cunning Action give them an extra bonus action?

@JeremyECrawford does the Rogue's Cunning Action give them an extra bonus action or does "only" mean to limit the actions available?

— Zach Tryon (@TryZach) July 9, 2016

Cunning Action gives you a bonus action and says what you can do with it. It's how bonus action features work. #DnD https://t.co/JOB0svMlRT

— Jeremy Crawford (@JeremyECrawford) July 9, 2016