Static export results in double download?

[deklanw]

I see that when I use static export my data is being put into two places: in a JS object within a script tag in the HTML file, and in its own JSON file. On loading a page from the top level, the data is hydrated from the script tag JS object, but then the JSON bundle is getting prefetched anyway (in anticipation of navigating back to this page clientside?).

Why is the data not just put into the JSON bundle only?