I am archiving this repository because of the below however, will keep it up and public for reference (particularly since the overwhelming majority of elements of the schema are still a part of Twitch's current GQL API.
Twitch has disabled introspection on their schema which results in the retrieval of their schema being no longer possible.
The current version of the schema are the last retrieved before Twitch disabled introspection, retrieved only a few hours before Twitch disabled it.
This contains the current schema and introspected schema which can be viewed to browse the available queries of the GQL API.