[] lets you use the random function, following the [CSS Values 5] specification.
<example.css>
/* becomes */
<example.expect.css>Note
Generated values are deterministic pseudo random numbers. Generating values twice with the same input will give the same result. The input length of the CSS source file is used as a random seed.
Given the dynamic nature of custom properties it's impossible to know what the variable value is, which means the plugin can't compute a final value for the stylesheet.
Because of that, any usage that contains a var is skipped.
The preserve option determines whether the original notation
is preserved. By default, it is not preserved.
<exportName>({ preserve: true })<example.css>
/* becomes */
<example.preserve-true.expect.css>