Motivation for dark selectors?

[boar-is]

buttonStyles have the following shape property:

shape: {
  square:
    'rounded-lg before:rounded-[calc(theme(borderRadius.lg)-1px)] after:rounded-[calc(theme(borderRadius.lg)-1px)] dark:after:rounded-lg',
  circle:
    'rounded-[9999px] before:rounded-[9998px] after:rounded-[9998px] dark:after:rounded-[9999px]',
},

What's the point of after:rounded-[9998px] dark:after:rounded-[9999px] and after:rounded-[calc(theme(borderRadius.lg)-1px)] dark:after:rounded-lg. Looks like an escape hatch for something. But I can't understand for what.