The viewBox attribute defines the position and dimension, in user space, of an SVG viewport.

The opacity attribute specifies the transparency of an object or of a group of objects, that is, the degree to which the background behind the element is overlaid.

A literal character specifies exactly itself to be matched in the input text.

The max attribute specifies the maximum value of the active animation duration.

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 vert-origin-y attribute indicates the y-coordinate in the font coordinate system of the origin of a glyph to be used when drawing vertically oriented text.

The class declaration creates a binding of a new class to a given name.

The repeatDur attribute specifies the total duration for repeating an animation.

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 text-anchor attribute is used to align (start-, middle- or end-alignment) a string of pre-formatted text or auto-wrapped text where the wrapping area is determined from the inline-size property relative to a given point.