Who has already studied googleapis.com/youtube/v3? Why doesn't live broadcast work in json feeds?

Question

Google

I tried everything, well, it doesn’t work, or I can’t find it, or I don’t understand how it’s right.
Why doesn't live broadcast work in json feeds?
I can't get json feed in V3 for broadcast search
https://developers.google.com/youtube/v3/sample_re...
The second question is how to get json feed in new api V3 in general search for (old names from api2)
" /most_viewed":
"/top_favorites":
"/most_discussed":
"/most_responded": Trying to
test.
Feed example
https://www.googleapis.com/youtube/v3/channels?par...
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PS . Youtube channel search demo test using v3, in...