var element is used to indicate that the text is a
variable and shouldn’t be taken literally. Instead, it’s a placeholder
where the contents should be replaced with your own value.
The example code would render as shown in Figure 1.
The following example shows a typical instruction about how to use a telephone system:
<p>To forward incoming calls to another extension, press <kbd>* 21 * <var>extension</var> #</kbd>.</p>
Use This For …
This element is used to indicate that the phrase is a variable of some kind—most likely in the context of showing an example value, as illustrated in the example HTML above.