Hi anonymous,
You can't run WikiTree on your own server any more than you could run Microsoft's website on your own server. The wikitree.com domain name is registered and the software that produces the website is proprietary and, although I am not part of the team that controls the software and provides the website, I am quite sure that it is not for sale.
The website you found is a work space where some WikiTree members who have the combination of skill and interest in developing apps that they are offering to donate for WikiTree's use are being developed and temporarily hosted while under development.
You leave me wondering why you are asking this question. THANX in advance for your answer..