At the moment, end-to-end is NOT production ready, and will likely undergo further hardening in the coming months. Use at your own risk.
I'm one of the original end-to-end authors, but haven't worked on it recently.
E2E extension is not production ready, but I myself am using the compiled version as it is, in my biased opinion, the most secure of existing PGP-in-the-browser extensions.
This sounds wrong, given that "end-to-end encryption" as a concept is very much production ready.
Proper capitalization would help; Google choosing a less overloaded name in the first place would have helped more.
We're going to have a very hard time talking about end-to-end crypto to consumers without at least one person confusing this with googles addon. (Thanks google)