Tested it last night, here is some feedback:
* Tried the obvious one, removing all Shorts sections and buttons from Youtube.com, it one-shotted it without apparent issues. Great!
* Tried a second one on youtube: increase the information density, shrinking the size of each video entry so more entries can fit in my screen. This one was a fail: it took 180+ seconds (vs. around 60 seconds of previous query), then some thumbnails got smaller (not all), while the physical space and padding for each entry was still there (so no real density was gained from the change)
* I think it'd be useful to be able to check the exact prompt that was used, so I can re-read it. It might even be interesting if it was editable, so I might decide to rephrase something from it. Otherwise, a chat-like interface would be interesting too, so the extension asks me what it interprets from my words before working to produce it. Right now, it feels like a very slow iteration process where I write something, it doesn't get it, and I keep trying to refine it and waiting around 60 to 100 seconds between results.
* I'd also like to see the actual filters that are being generated and applied on each change. This is so I can learn from them and probably edit them manually for refinement, as it can be faster to change a little bit in there, than trying to convey the exact phrasing of what I want to the LLM.
* This brought to mind the obvious (to me at least!) idea of how helpful it would be to have an uBlock Origin rule creator with same kind of LLM help. Filter rules are so esoteric and complicated for me (a C++ backend dev) that I always spend several hours of reading and DOM analysis as soon as I want to do anything that's not as simple as using the extension's element picker.
* A collection of curated changes would be useful. My first instinct was to check if there's a gallery of the most common changes that people request to some popular websites. I guess this can be analyzed and trends can be discovered.
* All in all, this looks amazing. It's a very useful and really gamechanging usage of LLMs! Changing website contents was out of reach for the general public before, so this extension could become their door to that.