If your WordPress site has a diary, it is wp-config.php. It stores the database name, the database user, the database password and the secret keys that protect logins. It is also the file people most often send around by email, upload to public repositories and paste into support chats.

Please do not. Anyone with that file can try to connect to your database, and if the database accepts outside connections, they may well succeed. The secret keys and salts can also help an attacker if they get hold of the rest of the site.

Handle it carefully. Keep a local copy in a protected place, not in a shared folder. Set its permissions to 600 or 640. When you move a site to a new host, edit the database details on the server rather than passing the file around. Never upload it over plain FTP, because the contents travel in readable form.

If you have already shared it somewhere you should not have, change the database password and the secret keys. It is a small chore. The alternative is a large chore, usually involving a client and a very long phone call.

Credit: Thank you to Claude for writing this filler content. It is an unsupervised learning task.