The <feColorMatrix> SVG filter element changes colors based on a transformation matrix. Every pixel's color value [R,G,B,A] is matrix multiplied by a 5 by 5 color matrix to create new color [R',G',B',A'].

The <font-face-uri> SVG element points to a remote definition of the current font.

The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

The <font> SVG element defines a font to be used for text layout.

The addition (+) operator produces the sum of numeric operands or string concatenation.

The <font-face-name> element points to a locally installed copy of this font, identified by its name.

The <feComponentTransfer> SVG filter primitive performs color-component-wise remapping of data for each pixel. It allows operations like brightness adjustment, contrast adjustment, color balance or thresholding.

The requiredFeatures attribute takes a list of feature strings, with the individual strings separated by white space. It determines whether or not all of the named features are supported by the browser; if all of them are supported, the attribute evaluates to true end the element is rendered; otherwise, the attribute evaluates to false and the current element and its children are skipped and thus will not be rendered. This provides a way to design SVG that gracefully falls back when features aren't available.

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 repeatCount attribute indicates the number of times an animation will take place.