Criterion Collection Subtitles

I recently subscribed to The Criterion Channel on my Apple TV (Model: Apple TV 4, Version: tvOS 12.3). It does not display Subtitles or Closed Captions (unless they are physically inserted in the film master). I assume the subtitles are digitally encoded separately somehow. If I watch the Criterion Channel on their web page on Safari, I get all the subtitles.

So, who programs/manages the Criterion Channel App on Apple TV? I wish to write them to ask if they plan to add that feature or for them to add that feature.

Regards.