Context: Get

Returns the current application context which may include possible sub-contexts. The application context can be 'Production', 'Development' or 'Testing'. Additionally each context can be extended with custom sub-contexts like: 'Production/Staging' or 'Production/Staging/Server1'. If no application context has been set by the configuration, then the default context is 'Production'.

Note about how to set the application context

The context TYPO3 CMS runs in is specified through the environment variable TYPO3_CONTEXT. It can be set by .htaccess or in the server configuration

See: http://docs.typo3.org/typo3cms/CoreApiReference/ApiOverview/Bootstrapping/Index.html#bootstrapping-context