Examples:
- html/min.html: minimal valid HTML document. It is insane however.
- html/min-sane.html: minimal sane HTML document. There are smaller valid ones, but they are insane.
- html/img.html
- html/img-broken.html: stackoverflow.com/questions/22051573/how-to-hide-image-broken-icon-using-only-css-html
- html/img-load-lazy.html: stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607#57389607
- html/iframe.html. Uses: html/iframe2.html, html/hello.txt and html/hello
- forms
- YouTube embeds