Hi Long Nguyen,
I can see that this confirmation page is using `wp_die()' to generate the email HTML confirmation page. Although I am very much in favour of an email confirmation function for signup security - This confirmation page delivers a very poor user experience to the end user! Please consider adding a hook or filter to allow developers to redirect users to a page of their choice, unless there is a security reason behind this decision that I am unaware of?
I look forward to your response.
Cheers
L