We handle navigation in Gatsby using the Link Component. So if we put both external and internal links in the Link element, we receive the following warning in the console:
External Link was detected in a link component. Use the link component only for internal links.

This is because the Link component is designed to interact with Gatsby's client-side navigation, which is better for single-page apps and uses the window.history API to update the URL without reloading the entire page.

So in case of external links, we should prefer a simple a tag and pass the href attribute.

Also gatsby prefetches the linked pages by starting a low priority request over a link, when we take the mouse on it onMouseOver, it makes the request high priority.