In theory, browser vendors could define a narrowly-scoped permission that only reports (hostname, ip), or roll this functionality into the browser UI, but neither seems likely to happen.
I made IPvFoo to promote IPv6 adoption, and wouldn't consider selling it for less than $10M USD. It probably won't ever be worth that much because it's an easily-cloned utility without a "moat", but it's more rational to set a price than refuse to sell under any circumstances.