V6 Update about single-spa HOT 1 CLOSED

Hi,
This is not required for single-spa to function, but is good to have (and you would have to change it to match the URL in the import map). Import maps use lazy loading by default, so browser will start fetching "single-spa" only when it's required (for example, at the first occurence of the import). Since single-spa's start method is typically one of the first things to run on the page, preloading instructs the browser to prioritize fetching it.

From mdn:

The preload value of the element's rel attribute lets you declare fetch requests in the HTML's , specifying resources that your page will need very soon, which you want to start loading early in the page lifecycle, before browsers' main rendering machinery kicks in. This ensures they are available earlier and are less likely to block the page's render, improving performance. Even though the name contains the term load, it doesn't load and execute the script but only schedules it to be downloaded and cached with a higher priority.

from single-spa.