The class MarkDownLink provides a data structure - but without its own properties and methods. It represents a set of several (class-)global variables. These variables serve the MarkDown class specifically for the MarkDown.Link() method to pass one argument instead of six.
Here you can see the full source code of the MarkDownLink class:
' Gambas class file Export Public Link As String Public Text As String Public Title As String Public Html As String Public Query As String Public Blank As Boolean