$Inspector is a global variable which gives a function to apply when the inspector is invoked from an interrupt menu.
Unicode: 2210. Alias: Esc coprod Esc. Infix operator. x ∐ y is by default interpreted as Coproduct[x,y]. ∐ x is by default interpreted as Coproduct[x]. Coproduct is used as ...
Reset Pan/Zoom resets the pan and zoom for the selected 3D graphic.
MinusPlus[x] displays as \[MinusPlus]x.MinusPlus[x, y, ...] displays as x \[MinusPlus] y \[MinusPlus] ....
SpanMaxSize is an option for selections that specifies the maximum size of spanning characters such as parentheses and brackets.
SpanMinSize is an option for selections that specifies the minimum size of spanning characters such as parentheses and brackets.
$PathnameSeparator is a string used as a separator when full file and directory names are constructed.
$UserDocumentsDirectory gives your default "documents" directory.
Verbatim patterns. Here the x_ in the rule matches any expression. The Verbatim tells Mathematica that only the exact expression x_ should be matched.
NotebookConvertSettings -> {opt_1 -> val_1, opt_2 -> val_2, ...} is a global option that specifies settings for converting imported legacy notebooks.