What does "non-normative" mean in this context?

From the ECMAScript language specification ECMA-262 page 1 Section 4

This section contains a non-normative overview of the ECMAScript language

The text goes on to say

ECMAScript is an object-oriented programming language for performing computations...

What does "non-normative" mean in this context?

Solution 1:

From sitepoint.com:

A normative section is a formal part of the recommendation. It contains rules that everyone must follow.

A non-normative, or informative, section contains additional information, advice and suchlike that isn't a formal part of the standard. That doesn't mean the information is less important, but it's not binding in the same way as the normative sections.

A good synonym, then, seems to be informal.

Solution 2:

'Normative' means 'what you should do' or 'what you must do', the rules that you are supposed to follow.

So 'non-normative' means 'what is recommended to be done', the suggestions on how to do things well (within the formal specifications laid out in the 'normative' part). It can also mean 'how people generally do things' whatever the formal rules say.

In a technical manual, something that is called 'non-normative' is most likely going to be general tips and examples on how to do what you want rather than a reference grammar or technical schema.