— Https://tools.ietf.org/html/rfc1894.html
— Heh, if they all follow an RFC like that, should be easy
— You can look for the multipart/report MIME type
— They also do message/delivery-status apparently
— Oooo ok, there's a header called X-Failed-Recipients :D that's all you really need!
— God they are all so inconsistent according to the people on SO there...
— Isn't email just great :/
— Https://github.com/eric-b/DSN-Parser