The patternContentUnits attribute indicates which coordinate system to use for the contents of the <pattern> element.

The letter-spacing attribute controls spacing between text characters.

The stroke attribute is a presentation attribute defining the color (or any SVG paint servers like gradients or patterns) used to paint the outline of the shape.

Iteration protocols aren't new built-ins or syntax, but protocols. These protocols can be implemented by any object by following some conventions.

The JavaScript exception "repeat count must be non-negative" occurs when the String.prototype.repeat() method is used with a count argument that is a negative number.

The JavaScript warning "-file- is being assigned a //# sourceMappingURL, but already has one." occurs when a source map has been specified more than once for a given JavaScript source.

Trailing commas (sometimes called "final commas") can be useful when adding new elements, parameters, or properties to JavaScript code. If you want to add a new property, you can add a new line without modifying the previously last line if that line already uses a trailing comma. This makes version-control diffs cleaner and editing code might be less troublesome.

An integer type which can be safely shared between threads.

The bitwise AND operator `&`.

A raw pointer type which can be safely shared between threads.