[ashyaspen]

https://kagi.com/orion/

Orion uses WebKit and has uBlock origin so I'm not so sure it's a limitation of WebKit itself.

[luuurker]

Kagi is trying to implement the Web Extensions API on top of WebKit, that's why some extensions work: https://kagi.com/orion/faq.html#extensions

Write enough code and you can make these extensions run on IE6. :P