Nextcloud Server Administration Manual, Release latest
Nextcloud configuration
Changes to the available options in config.php.
• The option blacklisted_files is now deprecated and replaced with forbidden_filenames
If there is a question hidden in your post, I couldn’t find it…
Just in case your post was meant as a question, and that question was what to do, then my answer would be to change the configuration parameter blacklisted_files to forbidden_filenames in the config.php.