Twitch integration got a LOT more diverse.
Clustertruck, includes within it a bot that connects to the streamers chat, and can thus send/receive messages to chat.
So the game just triggers the inbuilt bot to send a “poll open” to chat and then count the responses back. Once the timer is up it then feeds that to the game engine.
It’s just a chat bot. Most things via Twitch generally are. The new twitch integrations stuff hasn’t been around long enough for cleaner guides to exist since the docs and features are in flux.
TwitchDev has an example https://github.com/twitchdev/chat-samples