The following global variables are created and managed automatically by the [incr Tk] library. Except where noted below, these variables should normally be treated as read-only by application-specific code and by users.
When [incr Tk] is added to an interpreter, it executes the script "init.itk" in this directory. This script, in turn, looks for other script files with the name "init.xxx". Mega-widget libraries will be automatically initialized if they install a script named "init.xxx" in this directory, where "xxx" is the name of the mega-widget library. For example, the [incr Widgets] library installs the script "init.iwidgets" in this directory. This script establishes the "iwidgets" namespace, and sets up autoloading for all [incr Widgets] commands.