The JavaScript exception "mismatched placement" occurs when a private getter and setter are mismatched in whether or not they are static.

The values attribute has different meanings, depending upon the context where it's used, either it defines a sequence of values used over the course of an animation, or it's a list of numbers for a color matrix, which is interpreted differently depending on the type of color change to be performed.

The u1 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 first glyph in a kerning pair.

The unicode-range attribute defines the range of ISO 10646 characters possibly covered by the glyphs in a font.

The xlink:show attribute indicates how a linked resource should be opened and is meant for XLink-aware processors. In case of a conflict, the target attribute has priority, since it can express a wider range of values.

The Intl.PluralRules object enables plural-sensitive formatting and plural-related language rules.

The Intl.Segmenter object enables locale-sensitive text segmentation, enabling you to get meaningful items (graphemes, words or sentences) from a string.

The Intl.ListFormat object enables language-sensitive list formatting.

The toFixed() method of Number values formats this number using fixed-point notation.

The x1 attribute is used to specify the first x-coordinate for drawing an SVG element that requires more than one coordinate. Elements that only need one coordinate use the x attribute instead.