Manual:$wgRCEngines

Details
This variable is for configuring what engine classes will be used for what protocols when sending network updates for recent changes. See the main configuration variable, $wgRCFeeds for how to configure where recent changes information will be sent.

Usage
This variable is an associated array mapping the URI protocol to the fully qualified class name that will handle that protocol. The default value is:

This represents MediaWiki's built-in engine for sending RC updates over a UDP connection. More engines can be added by adding more keys or overriding existing ones.