What does it mean to say that XML was over-engineered?

[Roger L Costello <costello@mitre.org>]

Michael Kay wrote:

> Given that XML is over-engineered for many of the tasks
> that people were using it for, other standards better suited
> to a subset of those tasks were always going to emerge.

What does that mean, "over-engineered"? Does it mean, "too restrictive"? For example, XML does not allow two attributes with the same name to occur on an element. XML requires every start tag to have a matching end tag. Those are kind of restrictive. Is that what you mean by over-engineered? Or do you mean something else?

/Roger