The JavaScript exception "property name __proto__ appears more than once in object literal" occurs when an object literal contains multiple occurrences of the __proto__ field, which is used to set the prototype of this new object.

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 <feSpecularLighting> SVG filter primitive lights a source graphic using the alpha channel as a bump map. The resulting image is an RGBA image based on the light color. The lighting calculation follows the standard specular component of the Phong lighting model. The resulting image depends on the light color, light position and surface geometry of the input bump map. The result of the lighting calculation is added. The filter primitive assumes that the viewer is at infinity in the z direction.

The JavaScript exception "form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD'" occurs when an unrecognized string is passed to the String.prototype.normalize() method.

Apart from graphic primitives like rectangles and circles, SVG offers a set of elements to embed other types of content in images as well.

The <feGaussianBlur> SVG filter primitive blurs the input image by the amount specified in stdDeviation, which defines the bell-curve.

The JavaScript exceptions thrown by JSON.parse() occur when string failed to be parsed as JSON.

The <line> SVG element is an SVG basic shape used to create a line connecting two points.

The get syntax binds an object property to a function that will be called when that property is looked up. It can also be used in classes.

The <feFuncB> SVG filter primitive defines the transfer function for the blue component of the input graphic of its parent <feComponentTransfer> element.