What are ProtonMail’s headers? [closed]
What are the following headers in an end-to-end ProtonMail email?
X-Pm-Content-Encryption
X-Pm-Origin
X-Pm-Scheduled-Sent-Original-Time
X-Pm-Recipient-Authentication
X-Pm-Recipient-Encryption
It also mentions pgp-pm.
Are they specific to …