The classes in this directory are general utilities for use by any part of
MediaWiki. They do not favour any particular user interface and are not
constrained to serve any particular feature. This is similar to includes/libs,
except that some dependency on the MediaWiki framework (such as the use of
MWException, Status or wfDebug()) disqualifies them from use outside of
MediaWiki without modification.

Utilities should not use global configuration variables, rather they should rely
on the caller to configure their behaviour.