You require a user access token to access the subscribers endpoint
And the user access token needs to be of the user_id matching broadcaster ID in the request
The current user is determined by the OAuth token provided in the Authorization header.
User ID of the broadcaster. Must match the User ID in the Bearer token.
from Reference | Twitch Developers
You need authorization from the broadcaster to get the broadcasters subscriber count. (Since knowing the count lets you estimate the casters income from Twitch)
I missed this in your original message, as your topic is “general channel information” and this item isn’t general really.
Yes but it doesn’t have a user, so you won’t be able to get the users subscribers count (or email address) as there is no user on the token