The process below is the same for header or footer, just change the word in the Runtime_ManagedProperty_Load_Category function. This function will also load all the settings from the header/footer template into l.settings - usage of the l.all_settings in the Template_Render function takes care of that.

<mvt:assign name="l.cat_code" value="'featured'" />

<mvt:do name="l.ok" file="g.Module_Library_DB" value="category_load_code( l.cat_code, l.settings:_category)" />
<mvt:do file="g.Module_Feature_TUI_DB" name="l.null" value="Runtime_ManagedProperty_Load_Category( 'header', l.settings:_category:id, l.managedproperty )" />

<mvt:if expr="NOT ISNULL l.managedproperty:template_filename">
	<mvt:capture variable="l.settings:output">
		<mvt:do file="g.Store_Template_Path $ l.managedproperty:template_filename" name="l.null" value="Template_Render( l.null, l.all_settings )" />
	</mvt:capture>
	<p>Category header:</p>
	&mvt:output;
</mvt:if>