Steps to reproduce:
In the firefox webstore @ addons.mozilla.org/en-US/firefox/addon/librejs/ install LibreJS, once installed visiting websites with lots of non-free Javascript should have the Non-free Javascript blocked, instead when visiting sites like Youtube lots of non-free Javascript runs.
I tested this exact same addon in my MacOS Build of GNU IceCat and I got the expected results, that is all non-free Javascript on YouTube was blocked rendering YouTube useless (Which is good in my case).
Orion, OS version; hardware type:
Version 0.99.113.2-beta (WebKit 613.1.12), 2020 Apple M1 BacBook Air on MacOS 12 and a 2013 Thinkpad T440s Intel i5 on MacOS 11.
Image/Video:
Here is a photo of what I expected (This is the same addon in GNU IceCat):
and what I got in Orion:
