You are always welcome to run arbitrary JavaScript in the page. However, this does not mean the APIs other extensions use to block resource loads will work.
So it went from “it only supports JSON” to “yeah it supports more. I just don’t know if it will actually work. Because I haven’t looked into it’s capabilities”
That's a different question than was being asked. The current API does not really allow for anything like uBlock to exist. I expect if Chrome moves to a similar interface sites will start serving ads that 1Blocker will not be able to stop.
