Manual:$wgMWLoggerDefaultSpi/en

Details
The value should be an array suitable for use with. The created object is expected to implement the  interface. See $1 for additional details.

creates  instances that will discard all logging events.


 * (default) creates  instances which mimic the historic implementation of MediaWiki's   logging implementation.


 * creates loggers implemented by Monolog. See for configuration settings.