Comment 45 for bug 357864

I frequently use "dummy accounts" that never receive incoming mail. Their only
purpose is to let me edit the From field, that is otherwise uneditable.

Here is a workaround that works for me:
I made a simple Perl script that simulates a POP3 server. It accepts any
username and password whatsoever, and always reports an empty mailbox. This is
useful for advancing past Mozilla's account creation screen (which will not let
you create an account without specifying some kind of email server).

If anyone wants this script, email me at mozilla{at}krellan{dot}com and I will
send it to you.