Why there are changes in Wordpress core files in a Wordpress instance that was installed from Plesk Application catalog?

Question

Why there are changes in Wordpress core files (wp-admin/includes/upgrade.php, wp-includes/functions.php and wp-includes/load.php) in a Wordpress instance that was installed from Plesk Application catalog?

Answer

The mentioned changes in the Wordpress core files wp-admin/includes/upgrade.php, wp-includes/functions.php and wp-includes/load.php​ are part of the expected behavior of the Plesk Application Catalogue: These changes are implemented during Wordpress instance installation from Domains > example.com > Applications.

It is recommended to install Wordpress instances via Wordpress Toolkit from Plesk > Wordpress > Install. When a Wordpress instance is installed via Wordpress Toolkit, no changes are implemented in the Wordpress core files.