RE: Selectors: name find method and find signature

Thanks Boris, this is indeed all very helpful. I just wanted to point out that what you are calling "dictionaries" is largely covered by what I called "destructuring," on the input side at least. E.g.

> Furthermore, privileged code should never be working with raw page-provided ES objects, because doing that makes confused-deputy scenarios impossible to avoid in practice.  For example, dictionaries that will be operated on by privileged script first need to be coerced to a new clean object with a sane proto chain, only value properties, and the values themselves coerced to be safe to work with.  To the extent that we do not have a way to specify or perform such a coercion, we have a problem.

I believe this is almost entirely taken care of by destructuring.

Aside from that, much appreciate you spelling out what you find most important, and I think we're on the same page there.