Function fetch_a_modulepreload_module 

pub(crate) fn fetch_a_modulepreload_module(
    cx: &mut JSContext,
    url: ServoUrl,
    destination: Destination,
    global: &GlobalScope,
    options: ScriptFetchOptions,
    on_complete: impl FnOnce(&mut JSContext, bool) + 'static,
)

https://html.spec.whatwg.org/multipage/#fetch-a-modulepreload-module-script-graph