|MediaWiki File: UserMailer.php|
The UserMailer.php file contains a collection of static functions for sending mail.
UserMailer class 
This module performs a direct (authenticated) login to a SMTP Server to use for mail relaying if 'wgSMTP' specifies an array of parameters. It requires PEAR:Mail to do that. Otherwise it just uses the standard PHP 'mail' function.
EmailNotification class 
This module processes the email notifications when the current page is changed. It looks up the table watchlist to find out which users are watching that page and sends independent emails to each watching user.
The default email sender name WikiAdmin can be customized inside UserMailer.php to one that better suits your needs. For that, replace in line 482 the text 'WikiAdmin' with the one desired, taking care not to remove the single quotes:
$adminAddress = new MailAddress( $wgPasswordSender, 'WikiAdmin' );
Note that if you ever update your version of MediaWiki, you will have to reapply this change as it gets lost during upgrades.