The channel:read:redemptions scope is required by the Channel Points PubSub topic (https://dev.twitch.tv/docs/pubsub#topics) but not mentioned in the scopes overview (https://dev.twitch.tv/docs/authentication#scopes)
The channel:read:redemptions listed on the overview page (https://dev.twitch.tv/docs/authentication#scopes)
Either this has been added already or was there already.
Other comments from the GitHub issue thread:
Hmm, it's not the only scope that is mentioned in the PubSub docs and not listed in the general scopes in authentication. In fact, only bits:read is in both. Will check with the PubSub team if this is intentional, which is possible if they do not apply to v5/helix.
The others do, channel_subscriptions is under v5 and channel:moderate/whispers:read are under Chat and PubSub.
I suppose logically the same scope will be used for helix endpoints that may exist at somepoint for CRUDing Rewards. So I'd expect it to be on the summary page even if it's pubsub only…