Please provide some info on the what the special DUB icons mean. For instance, what does it mean when the D icon is there but it's crossed out? Or what does it mean when the DUB icon is grey instead of blue?

That means that those series have incomplete dubs. I’ve been trying to think of a clearer way to communicate this in the icons. I’ll add a note to the README soon.

Yeah, I think it's best to add a note to the README. Thanks for the clarification