Accessing "Extras" from purchased movies via AppleTV App on Firestick

Have an Amazon FireStick with the AppleTV app installed into it.

Also have a movie purchased from the iTunes Store which contains "Extras".

If I use the TV iOS app or the Apple TV website interface, I get a menu that allows me to access the "Extras", however I can find no such option in the AppleTV App for Firestick.

Am I missing something? Is there really no way to access the included Extras included in the movie purchase from the AppleTV FireStick app?

Please don't tell me to watch it on my iPhone and AirPlay it to the TV -- neither the TV nor FireStick support AirPlay. Yes, I might be able to use the Lightning AV dongle and an HDMI cable from the iPhone to play it on the TV but I'm trying not to do that.