Is attaching data to a page via loader only possible with the legacy API?

Documents on the outdated API are not relevant now for new projects, namely attaching data to a page (loader)? : https://docs.plasmic.app/learn/loader-pages/

Correct, it’s now called from the @plasmicapp/loader-* packages - please see the new quickstarts and the new API guides

(you can still pass in prop overrides as documented in the API guides)

Ok