The readme.html file in the WordPress root often reveals which WordPress version you run. That is useful to attackers mapping known exploits. There are other ways to fingerprint WordPress, but removing this file is still worth doing.
Check if it is public
Open https://yoursite.com/readme.html. If you see the WordPress readme page, the file is publicly reachable.
Fix with Security Ninja Pro
Enable the Remove Unwanted Files fix. It removes readme.html and similar leftover files in one step.
Fix manually (Free)
- Connect via FTP or your host’s file manager.
- In the WordPress root (same folder as
wp-config.php), deletereadme.html. - Optionally delete
license.txtthe same way if you do not need it publicly.
You can also deny HTTP access with server rules (for example .htaccess), but deleting the file is simpler.