This is a helpful and concise explanation. As I read the article, I continually wondered when custom elements would appear, and was surprised that they didn't.

This is a helpful and concise explanation. As I read the article, I continually wondered when custom elements would appear, and was surprised that they didn't. Adding this context around the link you mention would help. (I didn't click on the link because I was focused on absorbing your article in one go; now that I've looked at the link, I think that your sentence is much more concise for the reader.)