Using Emotes and Cheer icons in Extensions, permitted or not?

[Dist]

https://www.twitch.tv/p/en-gb/legal/trademark

Emotes

Without express permission, we do not allow use of emotes. Twitch and/or third parties own rights such as copyrights, trademarks, and/or rights of publicity in emotes on Twitch. Please note that in addition to us, the use of an emote may require permission from such third parties.

So you’ll need to contact twitch to gain explicit permission to use their emotes, and in the case of channel emotes you’ll need to contact the channel owner and ensure you have their permission as well.