Architecture Summit 2014/Configuration
MediaWiki is currently configured via a series of global variables that must be set in a PHP file by a user with file system access. This cluster of RfCs intends to allow the wiki to be configured using an on-wiki mechanism. Some of the motivations behind this can be found in the first RfC.
The first two RfCs, "Configuration database", and "Configuration database 2" discuss storing configuration parameters in a database table, while "Json Config pages in wiki" discusses using a JSON ContentHandler to store configuration options in a wiki page.
Some of these features have already been implemented in extensions: Configure provides basic on-wiki configuration functionality, and CentralAuth allows custom global user groups to be created on-wiki. The EventLogging, UploadWizard, and ZeroRatedMobileAccess extensions all currently store configuration options in JSON formatted pages.
See also: bug 26992, "Implement configuration database aka configuration management aka no shell excuse (tracking)"