Very short version: data:text/html, <body contenteditable>
You can also paste into a <body contenteditable>.
When you land on a site with a delayed paywall, you can copy out the content just before the popup, and then paste it into <body contenteditable> to view at your own leisure.
data:text/html, <textarea style="font-size: 1.5em; width: 100%; height: 100%; border: none; outline: none; font-family:monospace" autofocus />
mostly useless but I like it