This is intended to give users a chance to retrieve messages in cases where they have addressed the email to the wrong person, sent the wrong subject heading or made an error in the email content.
"This feature can't pull back an email that's already gone; it just holds your message for five seconds so you have the chance to hit the panic button," said Michael Leggett, Gmail user experience designer, in the Gmail blog.
"And don't worry: if you close Gmail or your browser crashes in those few seconds, we'll still send your message."
To add the feature, users need to turn on the Undo Send option in Gmail under Settings. They will then see a new 'undo' link on every sent mail confirmation.
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