If your fetch the .tml file directly, the server always does template processing. The return meta-data does not include a modify time, so proxies and browsers will not cache the page. However, if you fetch a .html file and there is a corresponding .tml file, then the server can check to see if the template is newer than the .html file. If it is, then the template is processed, the results are cached in the .html file, and the .html file is returned to the client. We use templates to provide the general look and feel of our site.
Most pages are static and just use the templates for standard headers, images, and so on.
Caching these pages makes sense because the template will generate the same thing every time. There are two configuration command that affect template results caching. DynamicOnly This is meant to be called from inside an HTML page. This prevents the results from being cached in the .html file. It means you maintain a .tml file, the browser can fetch the .html file, but the server will always process the template and return the data in a way that prevents caching by proxies and browsers.