It is showing on mine. Although, I think I remember early on checking in and they weren't. Maybe they need to download and cache the first time. I did have them on my json feed, but it seemed in the checklist I needed to manually use the Categories entry instead. Did you encounter that? Wondering if I did something wrong but in the end it worked, just had to associate via tags. Would prefer to have more manual control over it via the json file.
In your developer Dashboard there's a "Branding" section in the checklist. If you click in there it seems there's options for "Background Color" and "Font Color: Light/dark". Changing either of those two should get it changed. Just be aware because this is in the checklist it'll likely need to be resubmitted and go back thru the queue.
i did check that section...it was already set to have text show as 'dark'. so i'm tweaking the settings on that page a bit to see if i can get my text showing. i'll see if it works when they approve the update.
I found that they only seem to showup if you select a light background and dark text, anything else doesn't seem to show them, even when I set it to dark barkground and light txt, they do not show up.. Only light background and dark text made it work right.. Someone told me that it does work properly though but only on thier 4K TV, on a 1080p and 720p tvs it does not..