The website www.mage-os.org is operated by the group of companies and individuals who are listed as the original signatories of the open letter to the Magento community published on the website on 14. September 2021.
Their contact information can be found publicly on the respective websites.
Representative contact regarding all matters of the website is Vinai Kopp.
Address: Reichensteinstr. 36, 69151 Neckargemünd, Germany