ChangeAgent on "[Plugin: Wordfence Security] WP GB version reports>WordPress core file modified: wp-includes/version.php"

I have the GB version of WP installed and it keeps reporting that it finds an error in WordPress namely: core file modified: wp-includes/version.php

Line 37 that is being flagged reads

$wp_local_package = 'en_GB';

Why does it do this? How to fix?

Thanks.

https://wordpress.org/plugins/wordfence/