Low-level languages like C, have manual memory management primitives such as malloc() and free(). In contrast, JavaScript automatically allocates memory when objects are created and frees it when they are not used anymore (garbage collection). This automaticity is a potential source of confusion: it can give developers the false impression that they don't need to worry about memory management.

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 <title> SVG element provides an accessible, short-text description of any SVG container element or graphics element.

The fill attribute has two different meanings. For shapes and text it's a presentation attribute that defines the color (or any SVG paint servers like gradients or patterns) used to paint the element; for animation it defines the final state of the animation.

The async function* keywords can be used to define an async generator function inside an expression.

The <mask> SVG element defines a mask for compositing the current object into the background. A mask is used/referenced using the mask property and CSS mask-image property.

The y2 attribute is used to specify the second y-coordinate for drawing an SVG element that requires more than one coordinate. Elements that only need one coordinate use the y attribute instead.

The if...else statement executes a statement if a specified condition is truthy. If the condition is falsy, another statement in the optional else clause will be executed.

The JavaScript exception "import declarations may only appear at top level of a module" occurs when an import declaration is not at the top level of a module. This might be because the import declaration is nested in other constructs (functions, blocks, etc.), or more often because the current file is not treated as a module.

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.