OK, let's set formatSpecification explicitly to Empty if "num-format" value is empty. OASIS 1.2 says, in cases "an empty string" or "no value" is given, then no number sequence is displayed.

According to this is it correct to set formatSpecification to Empty if "num-format" value is empty in all lists, not only in headings?

But there is a simple statement in loadOdf function: if "num-format" is empty, then formatSpecification has a default value -- Numeric style. Isn't it strange, assuming all list styles numerical?

In D24852#553906, @boemann wrote:

All I'm saying is removing it completely is probably just as wrong as leaving it in. Maybe you could come up with some if case

In D24852#552012, @boemann wrote:

I think this will break those headings that actually should have numbering, so i think further investigation is needed with such cases

Fixed set value from "true" to expression " ! hasValue || ( hasValue && value != 0 ) "