<https://ru.venicebiennalesiria.com/2149-how-to-downgrade-from-macos-big-sur-beta-to-macos-catalina>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ru.venicebiennalesiria.com/2149-how-to-downgrade-from-macos-big-sur-beta-to-macos-catalina>