Often products with batteries in them. But also products with chemicals or generally products that cause could health, safety or fire concerns if not handled properly.
No it's not. "Dangerous goods" in shipping terms is a specific term for a very broad category with multiple subcategories of goods covered by (in this context) the international maritime code on dangerous goods which enumerates in mind numbing detail what goods are covered and what arent. Anybody in the business, who this site is for, will know what "dangerous goods" refers to. Just because you don't know the meaning of a term doesn't mean it's not very precisely defined.
You don’t just declare your goods as “dangerous,” there’s a bunch of subcategories and you have to explain why your things are dangerous and what to do about it. This report is just summarizing.