<https://protonmail.com/support/knowledge-base/third-party-email-client-integration-outlook-thunderbird-apple-mail-ect/#webpage>
<http://schema.org/description>
"ProtonMail leverages the technology within browsers which allows its ease of use. We are working on a solution for using ProtonMail with other email clients"
<https://protonmail.com/support/knowledge-base/third-party-email-client-integration-outlook-thunderbird-apple-mail-ect/?replytocom=1746>