@Davis I want custom CSS/JS/metatags to be injected to <head></head>
, not custom header ?
header != <head>
From the settings dashboard look it could look as simple as one window where you can put stuff like:
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1">
<script src="//xxxxxxxx" async="async"></script>
and so on.
Hope this helps ?