Very funny so see such an XML like syntax right after deciding to rip XML support out of Chrome. We're watching Google reinvent XSLT in real time, but now with tons of Javascript glue for some reason.
<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
<div> Here is some <em>HTML content</em>! <?marker name="placeholder"> <?marker name="placeholder1"> </div>
(only the first matching marker set is replaced.