HelpBrowserSettings -> {opt_1 -> val_1, opt_2 -> val_2, ...} is a global option that specifies settings for the legacy Help Browser.
HoldForm[expr] prints as the expression expr, with expr maintained in an unevaluated form.
HoldRest is an attribute which specifies that all but the first argument to a function are to be maintained in an unevaluated form.
x++ increases the value of x by 1, returning the old value of x.
In
(Built-in Mathematica Symbol) In[n] is a global object that is assigned to have a delayed value of the n\[Null]^th input line.
InputAutoReplacements is an option for cells and notebooks which specifies strings of characters that should be replaced immediately on input.
InputNotebook[] gives the current notebook into which keyboard input in the front end will be directed.
LightingAngle is an option for ReliefPlot and related functions that specifies the angle from which simulated illumination is taken to come.
LimitsPositioning is an option for UnderoverscriptBox and related boxes that specifies whether to change the positioning of underscripts and overscripts in the way ...
LinebreakAdjustments is an option for selections that sets parameters used for calculating where automatic line breaks should be inserted.