Construct 2 html5 export comes with complete index.html... but in Construct 3 the index.html only is this:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8"/>
<title>Meu Jogo</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no"/>
<link rel="manifest" href="appmanifest.json" />
<link rel="stylesheet" href="style.css"/>
</head>
<body>
<div id="fb-root"></div>
<script src="c2runtime.js"></script>
<script src="start.js"></script>
<script src="register-sw.js"></script>
</body>
</html>