app/pb_kits/playbook/pb_button/docs/_button_link

The link prop accepts a string that is used as an href value and causes the button to act as a link. The default behavior of a link is to open in the current window. You can optionally alter the link behavior by adding the newWindow prop (boolean), which will open the link in a new window, or by calling the target prop, which accepts _self, _blank, _parent, _top, child, or any string, allowing you to specify any link target.