X Environment Information opens a dialog box that displays the current attributes of the X front end environment (X only).
CellOpen is an option for Cell that specifies whether the contents of a cell should be explicitly displayed.
Environment["var"] gives the value of an operating system environment variable.
KCoreComponents[g, k] gives the k-core components of the underlying simple graph of g.KCoreComponents[g, k, "InDegree"] gives the k-core components with vertex in-degrees at ...
p?test is a pattern object that stands for any expression which matches p, and on which the application of test gives True.
PowerModList[a, s/r, m] gives a list of all x modulo m for which x^r \[Congruent] a^s mod m.
SameTest is an option whose setting gives a pairwise comparison function to determine whether expressions should be considered the same.
Setting
(Built-in Mathematica Symbol) Setting[expr] replaces control objects such as sliders or popup menus in expr by their settings.
StartOfLine represents the start of a line in a string for purposes of matching in StringExpression.
$GeoLocation is a settable global variable that specifies the default geodetic location to use.