是的，这可以使用CF7\'wpcf7_mail_tag_replaced\' 滤器

add_filter(\'wpcf7_mail_tag_replaced\', \'format_chackbox\',10,4);
function format_chackbox($replaced, $submitted, $is_html, $mail_tag){
  //you can check if this is the right field if need be.
  if(\'my-checkbox-field\' != $mail_tag->field_name()) return $replaced;
  //$submitted contains the raw submitted data.
  //$replaced is the formatted data, you can use either.
  $a = explode(\',\', $replaced);
  //check if you have multiple values and the email accepts html (set with the use html checkbox in the mail notification settings).
  if(is_array($a) && $is_html){
    $replaced = \'<ul>\'.PHP_EOL;
    foreach($a as $v) $replaced .= \'<li>\'.trim($v).\'</li>\'.PHP_EOL;
    $replaced .= \'</ul>\'.PHP_EOL;
  }
  return $replaced;
}