The stroke-opacity attribute is a presentation attribute defining the opacity of the paint server (color, gradient, pattern, etc.) applied to the stroke of a shape.

The stop-opacity attribute defines the opacity of a given color gradient stop.

The u2 attribute specifies list of Unicode characters (refer to the description of the unicode attribute of the <glyph> element for a description of how to express individual Unicode characters) and/or ranges of Unicode characters, which identify a set of possible second glyph in a kerning pair.

The JavaScript exception "invalid Array.prototype.sort argument" occurs when the argument of Array.prototype.sort() (and its related methods: Array.prototype.toSorted(), TypedArray.prototype.sort(), TypedArray.prototype.toSorted()) isn't either undefined or a function which compares its operands.

The JavaScript exception "called on incompatible target (or object)" occurs when a function (on a given object), is called with a this not corresponding to the type expected by the function.

Whereas HTML defines a webpage's structure and content and CSS sets the formatting and appearance, JavaScript adds interactivity to a webpage and creates rich web applications.

The JavaScript exception "duplicate capture group name in regular expression" occurs when a regular expression pattern contains two or more named capturing groups with the same name, and these capture groups could be matched at the same time.

The stitchTiles attribute defines how the Perlin Noise tiles behave at the border.

The stroke-linecap attribute is a presentation attribute defining the shape to be used at the end of open subpaths when they are stroked.

The v-alphabetic attribute defines indicates the alignment coordinate for glyphs to achieve alphabetic baseline alignment. The value is an offset in the font coordinate system relative to the glyph-specific vert-origin-x attribute.