Manual:AdminSettings.php

Details
The requirement for  (along with supporting file  ) was rudimentarily removed in MediaWiki 1.16. Prior to MediaWiki 1.16,  was used to store database authentication credentials for maintenance scripts and to control the availability of. It has finally been removed completely in MediaWiki 1.23.

Upgrading
If upgrading from a pre-1.16 version of MediaWiki to version 1.16 or later, the variables set in  file can be safely removed. is no longer needed. If it still exists, it will be loaded by maintenance scripts to retain backward compatibility.

Prior to 1.16
Manually create  in the root directory of the MediaWiki installation. Typically, this is done by renaming  to   and then editing   appropriately.

should set three variables:
 * - the name of a database account that has sufficient privileges to run the database maintenance scripts. For MySQL databases, this account should have "superuser" privileges. For PostgreSQL databases, this account should be the same account used for $wgDBuser.
 * - the password for the  account.
 * - controls the availability of.

Security
AdminSettings.php contains sensitive information (account names and passwords) that can help an attacker compromise your database management system. Ensure that you've taken the relevant preventative measures listed in Manual:Security and Manual:Securing database passwords.

PostgreSQL-specific issues
If using PostgreSQL with your MediaWiki installation, the authentication credentials used for  and   should be the same as the credentials used for   and. This is necessary to ensure that the owner for new tables is set correctly.