That message means you changed the file, that you edited. It is a warning in case you didn't change the file yourself, in case there is an intruder in the system changing the files, or in case you are uploading the add-on and the files didn't finish uploading. Since you DID change this file yourself, there is nothing to worry about.
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If you are still receiving the same exact error message, possibly your PHP installation has cached the old file (before the edit) and you have a long-lived cache life. To clear the cache, you can restart your server's PHP process (such as PHP-FPM).
EDIT: Since it is working now, you tried again after the PHP cache expired.
Since the installation is now working, we will be adding this change to the next build to help other users who might have MariaDB 10.6. Thank you for reporting the issue.