If possible, the "Open in Codepen" buttons are implemented as <button> elements, but should be <a> elements. This would:
Provide a more-accurate representation of what they do (navigate you do a different page), improving accessibility
Be a better semantic representation of their purpose, for the same reason
Allow users the control to use them in the way that suits them best, e.g. right-click and "Bookmark link...", "Save link as..." etc., or drag-and-drop the link into a specific other tab or window
If possible, the "Open in Codepen" buttons are implemented as
<button>elements, but should be<a>elements. This would: