Passster: Send e-mail once password was used.

functions.php

<?php

add_action( 'passster_validation_success_list', function( $password, $password_list_id, $post_id ) {
	// prepare and send the e-mail.
	$to      = '[email protected]';
	$subject = 'Password ' . $password . 'was used';
	$headers = array( 'Content-Type: text/html; charset=UTF-8' );
	$body    = 'Password ' . $password . ' form passwords list ' . get_the_title( $password_list_id ) . ' was used to unlock content on ' . get_permalink( $post_id );

	// Now we can send the e-mail.
	wp_mail( $to, $subject, $body, $headers );
}, 2, 10 );