The bitwise OR assignment (|=) operator performs bitwise OR on the two operands and assigns the result to the left operand.

The InternalError object indicates an error that occurred internally in the JavaScript engine.

The clip-path presentation attribute defines or associates a clipping path with the element it is related to.

Symbol is a built-in object whose constructor returns a symbol primitive — also called a Symbol value or just a Symbol — that's guaranteed to be unique. Symbols are often used to add unique property keys to an object that won't collide with keys any other code might add to the object, and which are hidden from any mechanisms other code will typically use to access the object. That enables a form of weak encapsulation, or a weak form of information hiding.

The isFinite() function determines whether a value is finite, first converting the value to a number if necessary. A finite number is one that's not NaN or ±Infinity. Because coercion inside the isFinite() function can be surprising, you may prefer to use Number.isFinite().

The <metadata> SVG element adds metadata to SVG content. Metadata is structured information about data. The contents of <metadata> should be elements from other XML namespaces such as RDF, FOAF, etc.

The <use> element takes nodes from within the SVG document, and duplicates them somewhere else. The effect is the same as if the nodes were deeply cloned into a non-exposed DOM, then pasted where the use element is, much like cloned template elements.

The bitwise OR (|) operator returns a number or BigInt whose binary representation has a 1 in each bit position for which the corresponding bits of either or both operands are 1.

The by attribute specifies a relative offset value for an attribute that will be modified during an animation.

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.