with other kinds of fruit spread named **“jam” or equivalent terms in other languages. **

Here we have marmalade or syltetøj.
And they used to have distinct meanings, which I am not quite familiar with. I think for marmalade there originally was a requirement of a certain level of sugar content. But IMO such a requirement would not make much sense today.

Seems to me the article is doing a piss poor job at giving a concise description of what the regulation actually means.