OK, confirmation at least that all this wasm stuff is invisible server hosting; it does not appear to actual users. So instead of copying your files to a web server, you instead use their tools to compile an application which embeds all your files, and then deploy that compiled binary application on Fastly's infrastructure. That seems complex, but it maybe works (at least, on trivially small static sites). This makes problem diagnosis sound hard to me, but maybe it's OK, if complicated.