Can someone explain the setting 'Include original sender in email headers'
In settings, SimpleLogin has the option:
>Include original sender in email headers
>SimpleLogin forwards emails to your mailbox from the reverse-alias and not from the original sender address.
If this option is enabled, the original sender addresses is stored in the email header X-SimpleLogin-Envelope-From and the original From header is stored in X-SimpleLogin-Original-From. You can choose to display this header in your email client.
As email headers aren't encrypted, your mailbox service can know the sender address via this header.
I need help understanding this. Especially the part where it says 'As email headers aren't encrypted, your mailbox service can know the sender address via this header.' I am using SimpleLogin with Proton. So does this mean that checking 'Include sender address in email headers' make it less secure?