Manual:$wgConfigRegistry

Server URLs and file paths: $wgConfigRegistry
Registry of factory functions to create config objects
Introduced in version:1.23.0 (Gerrit change 109850; git #I5a5857f)
Removed in version:Still in use
Allowed values:(array)
Default value:
[
	'main' => 'GlobalVarConfig::newInstance'
]

Details

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Registry of factory functions to create Config objects. MediaWiki core provides GlobalVarConfig and HashConfig; extensions can create their own implementations of the interface if they wish, although it's typically not needed. The main key must be set, and the value should be a valid callable. It's used for creating the main config object (available as the MainConfig service).