The JavaScript exception "invalid property name in regular expression" or "invalid class property name in regular expression" occurs when the \p and \P Unicode character class escapes are not followed by a valid Unicode property name and/or value.

The fy attribute defines the y-axis coordinate of the focal point for a radial gradient.

The await using declaration declares block-scoped local variables that are asynchronously disposed. Like const, variables declared with await using must be initialized and cannot be reassigned. The variable's value must be either null, undefined, or an object with an [Symbol.asyncDispose]() or [Symbol.dispose]() method. When the variable goes out of scope, the [Symbol.asyncDispose]() or [Symbol.dispose]() method of the object is called and awaited, to ensure that resources are freed.

The diffuseConstant attribute represents the kd value in the Phong lighting model. In SVG, this can be any non-negative number.

The dur attribute indicates the simple duration of an animation.

The intercept attribute defines the intercept of the linear function of color component transfers when the type attribute is set to linear.

The JavaScript exception "illegal character" occurs when the lexer reads a character that's not part of a string literal, and the character cannot constitute a valid token in the language.

The fetchpriority attribute provides a hint to the browser about the relative priority to use when fetching an external resource. This works the same way as the fetchpriority attribute for the HTML <img> and <script> elements.

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

The href attribute defines a link to a resource as a reference URL. The exact meaning of that link depends on the context of each element using it.