I don’t think @ links was initially supported when they did launch which is interesting tbh.
Edit: Apparently was never resolved as far as I can see lol
Either way, I should probably also mention certain Twitch links such as https://twitch.tv/giftcards/buy, which will open the Twitch giftcards page in your local region for example.
Afaik there’s no other redirect links on Twitch though.
Whilst I’m here, block https://youtube.com//opensearch. Downloads a harmless XML file.