WidgetReference[id] looks up an existing widget instance using identifier id and return the underlying object.
FullReport is an option to hypothesis test functions that specifies whether all report information should be returned.
KnownVariance is an option to statistical confidence interval and hypothesis test functions that specifies the value of the population variance.
ChartLabels is an option for charting functions that specifies what labels should be used for chart elements.
ImageMargins is an option that specifies the absolute margins to leave around the image displayed for an object.
NumberSeparator is an option for NumberForm and related functions which gives the string to insert at breaks between digits.
SelfLoopStyle is an option for GraphPlot and related functions that specifies how to draw self-loops that connect a vertex to itself.
$MinMachineNumber is the smallest positive machine-precision number that can be used on a particular computer system.
$ProcessorCount gives the number of processor cores available on the computer system on which Mathematica is being run.