To use the file just include in your page template or HTML Header region just make sure it loads after the built in HTML DB javascript libraries so that it properly overides/extends the built in functionality.
If you want to use this file on htmldb.oracle.com it can be added in using this tag
<script src="https://static.oracle.com/cdn/apex/24.2.6/carl/htmldb_examples/htmldb_remix.js" type="text/javascript"></script>
You can if you want just cut out the functionality you want instead of including the whole javascript file but your on your own at that point.