Give a link an [up-layer=new] attribute to extract a CSS selector from the destination
and open the fragment in a modal dialog.
No server-side changes required.
<main>
<p>Story summary</p>
<a href="/?originalUrl=https%3A%2F%2Funpoly.com%2F%26quot%3Bfull.html%26quot%3B%2520up-layer%3D%26quot%3Bnew%26quot%3B%26gt%3B%2520%2520%2520%2520Read%2520full%2520story%2520%2520%26lt%3B%2Fa%26gt%3B%26lt%3B%2Fmain%26gt%3B%253C%2Fcode">
<main>
<h2>Full story</h2>
<p>Lorem ipsum dolor sit amet.</p>
</main>