Here is a list of all variables with links to the structures/unions they belong to:

$align : Table
$barChar : Progress
$bottomLeftCornerChar : Box
$bottomRightCornerChar : Box
$char : HLine
$clearScreen : MultiSelector
$content : Box
$currentIndicatorIndex : Loader
$currentValue : Progress
$data : Table
$decimalPoint : NumberEntry
$decimals : NumberEntry
$footer : Table
$format : DateEntry
$header : Table
$horizontalAlign : Box
$horizontalBorderChar : Box
$indicators : Loader
$intersectionChar : Table
$label : DateEntry, MultiSelector, NumberEntry, PasswordEntry, SingleSelector, TextEntry, TextMultiLineEntry, Loader
$maxValue : Progress
$options : MultiSelector, SingleSelector
$outputType : NumberEntry
$parser : DateEntry, NumberEntry
$percentPrecision : Progress
$prompt : MultiSelector, SingleSelector
$returnOptionKey : MultiSelector, SingleSelector
$selection : MultiSelector
$selectionInvalidMessage : MultiSelector, SingleSelector
$simpleHorizontalBorderChar : Table
$specialHorizontalBorderChar : Table
$startTime : Progress
$thousandsSep : NumberEntry
$times : Progress
$topLeftCornerChar : Box
$topRightCornerChar : Box
$unitFormatter : Progress
$units : Progress
$verticalBorderChar : Box, Table
$width : Table