[Feature request] Custom information on home screen / Download button

[DasDunkel]

Could an option be added to include custom information to the home screen

For example, I'd like to be able to inform users of the service that all emails will be deleted after 30 days, so they should make backups of any emails/addresses they want to keep, which brings me onto another less essential request;
A button to quickly download a single email, or download/delete all emails for an address.