TemplateEnvironment

Questions
, ,
1

Here is a simple template:

template = XMLTemplate["
   <html>
   	<body>
   		<center> <wolfram:slot/> </center>
   	<body>
   </html>"];

The following works fine and is understood:

SystemOpen @ Export[ 
  	"e:\\folder\\page1.html",
  	Rasterize[Plot[Sin[x], {x, -3, 3}]], 
  	"HTMLFragment", 
        "TemplateFunction" -> template
  ]

Now the sample from the documentation:

SystemOpen @ Export[ 
  	"e:\\folder\\page1.html",
  	Rasterize[Plot[Sin[x], {x, -3, 3}]], 
  	"HTMLFragment", 
  	"TemplateEnvironment" -> <|
    		"Theme" -> "Blue",
    		"Brand" -> "mybrand",
    		"PageTitle" -> "my pagetitle",
    		"PageDescription" -> "This is a sine plot",
    	"Footer" -> "The footer"
    	|>
  ]

It uses “TemplateEnvironment”. The question is where can I find the source template file where the above key value pairs are used. Can’t find where it picks up the html template file to merge it in.