Stay tuned, we're working on creating a more granular permissions policy as this is a concern for many users. We can promise you that we don't store or read any information on the sites you visit, but of course it would make users feel more comfortable if they could read it themselves in the permissions when installing.

I'd throw this in the bucket of things browsers could do better. There is no extension API that just lets an extension declaratively rewrite links. The plugin has to ask for a mile to use an inch, because that's what's available.