I want to change the format of the "Date"-column in the message list in Thunderbird.
For mails from today, I want to display only the time, not the date.
For mails from before today, I want to display only the date, not the time.
This is the same setup mutt uses. I know of the Date display format wiki article, which describes how to change the date format, but you can only switch between five predefined formats, and none of them is "Date only".
I also know of the ConfigDate extension, but it's got the same limitations, you can't define a new date format.