How to force full screen of interactive embedded player

[BarryCarlyon]

Sounds like it might be broken until the upcoming player changes:

Twitch Embedded Player Updates in 2020

Changes are coming to Twitch embedded experiences! We’re updating the way the embedded video player is initiated so that it takes advantage of all the performance improvements we’ve made to the on-site player over the last year. Today we’re announcing the first of multiple changes. Details and examples are included below to begin making code changes at your convenience. There is currently no deadline; a timeline will be provided via a future update to this post. Update (2020/05/13): These chan…