<div> <?marker name="placeholder2"> </div>

<template for="placeholder2"> <?marker name="placeholder1"> <?marker name="placeholder1"> </template>

<template for="placeholder1"> <?marker name="placeholder"> <?marker name="placeholder"> </template>

<template for="placeholder"> Here is some <em>HTML content</em>! </template>

Before you couldn't make this dangerous (without JS) because there was no way to auto expand the templates