Twitch doesn’t validate/verify/test the local application generally speaking.
Their primary concern is the code uploaded to the Twitch CDN and their testing doesn’t cover any local applications/game mods the broadcaster may need.
I run an extension thats been live since extensions existed, that does exactly what you propse.
- Local App reads a game file
- Local app sends data to my EBS
- My EBS parses and copies relevant data to the extension over Twitch PubSub.
The only thing in the guidelines, that is related, is you cannot require a viewer to download/install something to use an extension, but broadcasters, it’s basically expected for a lot of game related extensions