The <use> element takes nodes from within the SVG document, and duplicates them somewhere else. The effect is the same as if the nodes were deeply cloned into a non-exposed DOM, then pasted where the use element is, much like cloned template elements.

The clip-path presentation attribute defines or associates a clipping path with the element it is related to.

The accent-height attribute defines the distance from the origin to the top of accent characters, measured by a distance within the font coordinate system.

The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

A regular expression (regex for short) allow developers to match strings against a pattern, extract submatch information, or simply test if the string conforms to that pattern. Regular expressions are used in many programming languages, and JavaScript's syntax is inspired by Perl.

The increment (++) operator increments (adds one to) its operand and returns the value before or after the increment, depending on where the operator is placed.

The logical AND assignment (&&=) operator only evaluates the right operand and assigns to the left if the left operand is truthy.

The dx attribute indicates a shift along the x-axis on the position of an element or its content.

The font-size-adjust attribute allows authors to specify an aspect value for an element that will preserve the x-height of the first choice font in a substitute font.

The extends keyword is used in class declarations or class expressions to create a class that is a child of another class.