Show Debugger Tools Window toggles the display of the Debugger Tools window on or off.

Show Stack Window toggles the display of the evaluation stack window on or off.

Evaluation > Debugger Controls > Step (Mathematica Menu Item)

Step makes the debugger stop at the beginning of the next expression.

Step Out stops the debugger after finishing all evaluations in a stack.

Evaluation > Debugger Controls > ... (Mathematica Menu Item)

Toggle Breakpoint toggles a breakpoint on or off.

[Right-click] > Version Advisory (Mathematica Menu Item)

Version Advisory checks for input from previous versions of Mathematica that should be updated for compatibility with the current version.

Accumulate (Built-in Mathematica Symbol)

Accumulate[list] gives a list of the successive accumulated totals of elements in list.

ArcSech (Built-in Mathematica Symbol)

ArcSech[z] gives the inverse hyperbolic secant sech -1 (z) of the complex number z.

ArrayPlot (Built-in Mathematica Symbol)

ArrayPlot[array] generates a plot in which the values in an array are shown in a discrete array of squares.

BesselK (Built-in Mathematica Symbol)

BesselK[n, z] gives the modified Bessel function of the second kind K_n (z).