Minor clarification — When you say “The bookmark object requires the info attribute, which contains the metadata attribute,” that doesn’t make sense in XML, since attributes can’t contain further attributes.

Looking at your screenshot, it appears you mean to say the element requires an element as a child, and it in turn requires a child element.

I think also when you say “folder object” you mean element, which does indeed have a folded attribute. The word “object” in XML syntax doesn’t really pertain.

And then I see you are an e-book reader too. I too am reading almost entirely Plucker titles — have you found any English titles in FB2?

Roger