Why does Sveltekit skip code block that would result in ReferenceError during SSR

By default sveltekit does SSR followed by CSR, so when I try to access window object from the server side I get an error as expected.

<script lang="ts">  import { browser } from "$app/environment";  async function hello_world() {    console.log(`hello world from: ${browser ? "client" : "server"}`);    console.log(window.localStorage);    console.log("after accessing localStorage");  }  hello_world();</script><p>Hello World!</p>

ReferenceError: window is not defined

However, if I use the await block, then sveltekit seems to magically skip the block of code that would cause the error + all following lines.

<script lang="ts">  import { browser } from "$app/environment";  async function hello_world() {    console.log(`hello world from: ${browser ? "client" : "server"}`);    console.log(window.localStorage);    console.log("after accessing localStorage");  }</script>{#await hello_world()}<p>Hello World!</p>{/await}

hello world from: client<Storage object>after accessing localStorage

hello world from: server

I was expecting both cases to result in the same ReferenceError, so I would like to understand why and how await causes sveltekit to skip not only the problematic code but also the lines following it.