I\'m new to Mustache.
Many templating languages (e.g., Django / Jinja) will let you extend a \"parent\" template like so...
You could use variables containing HTML. A "triple mustache" like {{{variable}}}
will return unescaped HTML. It's not exactly the same as template extensions, but you could render frontpage-content.html and then put its output in a content
variable that gets passed to base.html.
(I added -content to the frontpage.html filename with the expectation that such a naming pattern will help keep the filenames manageable.)