includeCssFile and includeJsFile doesn't output {{ siteUrl }} It seems that when calling a CSS or JS file include, if the path contains {{ siteUrl }} it outputs {{ siteUrl }} in the html that is generated.

Like so;
&lt;link rel="stylesheet" type="text/css" href="{{ siteUrl }}css/styles.css"/&gt;

Which should be (for example);
&lt;link rel="stylesheet" type="text/css" href="http://site.url/dev/css/styles.css"/&gt;

Anything I'm missing here?
When you want to output Twig variables inside another Twig tag, you shouldn't include the braces around the variable.

So this:

{% includeCssFile "{{ siteUrl }}css/modul.min.css" %}
{% includeJsFile "{{ siteUrl }}js/ui.min.js" %}


Should be this:

{% includeCssFile siteUrl ~ "css/modul.min.css" %}
{% includeJsFile siteUrl ~ "js/ui.min.js" %}


These examples use the concatenation operator (~) to join the value held in the siteUrl variable to the string holding the path to the CSS or JS file to be included.