First I want to thank David_Rothstein who, on the D7.56 Update page, wrote "No changes have been made to the .htaccess, web.config, robots.txt or default settings.php files in this release, so upgrading custom versions of those files is not necessary". That does make things a bit easier, as we do not need to manually check if anything has changed.
In that spirit, imagine if the update pages also added [fictitious example] :
What has changed : in comparison to the previous release (#.##), the updated files are within in the folder /includes and in the file update.php . You may therefore only change your old files with these, before running /update.php .
For example, when I was using phpBB forum, they would offer just the updated files. Thank you.
- using Drupal since around 2002.