Pretty simple really, it should take an email and display its contents. Sadly emails are not that simple, inline pdfs, strange character sets, multipart/alternate parts containing different data and just what scope should multipart messages with a Content-Disposition filename have?
Basically, partly as a utility and partly as an exercise in masochism, I want to make a program that will render absolutely any email in a sane manner. Then hopefully I can get back to making a sane email composer.