How can the class mail::decode_header() be effectively utilized to decode and display email header content in PHP?

To decode and display email header content in PHP, you can use the mail::decode_header() method provided by the PHP IMAP library. This method decodes MIME header elements like Subject, To, From, etc., which may contain non-ASCII characters or be encoded in different formats like base64 or quoted-printable. By utilizing this method, you can properly decode and display email header information in a human-readable format.

// Connect to the IMAP server
$imapStream = imap_open('{imap.example.com:993/imap/ssl}INBOX', 'username', 'password');

// Fetch the email headers
$headers = imap_fetchheader($imapStream, $emailNumber);

// Decode the headers using mail::decode_header()
$decodedHeaders = mail::decode_header($headers);

// Display the decoded headers
foreach ($decodedHeaders as $header) {
    echo $header . "<br>";
}

// Close the IMAP connection
imap_close($imapStream);