What this Bootstrap Utility API class does
Sets the shorthand border-top property of an element. The CSS property "border-top" is used to set the width, style, and color of the top border of an HTML element.
Example usage & available classes
In the example below, we are making the utility responsive, which means you can also use it per breakpoint: ".border-top-lg"
"border-top": map-merge( map-get($utilities, "border-top"), ( responsive: true ) )