> But once the data leaves the browser there is no way to know, wouldn't you consider to partner with Gmail(or others) and appear as an addon to an already trusted company in order to start off the business ?

Also, I understand the concern and that Paul most likely will not trust their secrets to anyone. The problem is that's not a business, but a beautiful hobby project that I honestly love, so it's unlikely that I will ever spend time rewriting it and then paying Google $15K (https://www.gmass.co/blog/google-oauth-verification-security...) so they could vet me.