PGP has long been available in command-line form, as a plug-in for IMAP-based email clients, and it clumsily interoperates with Gmail by cut-and-paste. Chromebook users also have never had a good solution; choosing between strong crypto and a strong endpoint device is unsatisfactory. E2EMail is not a Google product, its now a fully community-driven open source project, to which passionate security engineers from across the industry have contributed.”]
Source: https://security.googleblog.com/2017/02/e2email-research-project-has-left-nest_24.html