The documentation states that AMP HTML documents MUST
<script async src="https://cdn.ampproject.org/v0.js"></script>
To be a valid AMP document, you must use the
<script async src="https://cdn.ampproject.org/v0.js"></script> tag.
Bootstrap JS for menus). You also could assign the AMP document to the canonical tag, and then serve it to folks who do not have unrestricted access to the internet (and hence the Google CDN).