How to make the e-mail address of the writer a part of the text
Topic on Extension talk:ContactPage
Got a resolution for LocalSettings.php:
$wgHooks['EmailUser'][] = function ( &$address, &$from, &$subject, &$text, &$error ) {
...
$text = $text . 'E-Mail-Adresse:: ' . $from->address;
...
};