alt Hacker NewsSo, HTML did have includes and they fell out of favor.
The actual term include is an XML feature and it’s that feature the article is hoping for. HTML had an alternate approach that came into existence before XML. That approach was frames. Frames did much more than XML includes and so HTML never gained that feature. Frames lost favor due to misuse, security, accessibility, and variety of other concerns.
Unlike Framesets I think XML includes were never really supported in many browsers (or even any major browsers)?
I still like to use them occasionally but it incurs a "compilation" step to evaluate them prior to handing the result of this compilation to the users/browsers.