The <ellipse> SVG element is an SVG basic shape, used to create ellipses based on a center coordinate, and both their x and y radius.

The parseInt() function parses a string argument and returns an integer of the specified radix (the base in mathematical numeral systems).

The typeof operator returns a string indicating the type of the operand's value.

The patternUnits attribute indicates which coordinate system to use for the geometry properties of the <pattern> element.

The maskUnits attribute indicates which coordinate system to use for the geometry properties of the <mask> element.

The min attribute specifies the minimum value of the active animation duration.

The glyph-orientation-vertical attribute affects the amount that the current text position advances as each glyph is rendered.

The JavaScript strict mode-only exception "0-prefixed octal literals are deprecated; use the "0o" prefix instead" occurs when deprecated octal literals (0 followed by digits) are used.

A block statement is used to group zero or more statements. The block is delimited by a pair of braces ("curly braces") and contains a list of zero or more statements and declarations.

The limitingConeAngle attribute represents the angle in degrees between the spot light axis (i.e., the axis between the light source and the point to which it is pointing at) and the spot light cone. So it defines a limiting cone which restricts the region where the light is projected. No light is projected outside the cone.