[stockhorn]

off topic, but why does the page (step 2) rant about protonmail?

Can somebody elaborate?

>Be advised that Protonmail is generally known to be a pretty bad email host. [...] Not to mention their mistreatment of open source and false promises of security! You should consider a different mail provider.

[protonmail]

Proton Mail Bridge normalizes line breaks in plaintext emails to conform with cleartext PGP signing rules. This sometimes creates problems with third-party cleartext signing which is used by programs such as git-send-email. Third-party signing is not actually a supported use case of the Bridge and this can be worked around by requesting a SMTP submission token.