wpgraft never reads Oxygen’s data. There is no exporter and no importer anywhere in this. It reads the page as your browser rendered it: the real elements and the real computed styles on each one, at every width you ask for. It then builds that as a Shopify section made of theme blocks, with every style in one of the blocks’ own settings. Nothing that arrives depends on Oxygen still being there.
This move crosses platforms: Oxygen is WordPress, Shopify is a hosted store. There is no plugin and no export on either side. The copy is made from the page Oxygen rendered and written into your Shopify theme from your own admin tab, and your Oxygen page stays where it is. What moves is the design; products, orders and checkout are set up in Shopify itself.