That's the point of the partial publish - the author is signalling that even though they have a draft of this particular page, they don't want to publish it at this time. So we need to remove it from the binder as sent to the epub builder. This leads to two cases: if it's completely new, just delete it. If it's a rev of existing content, we need to replace it w/ a docpointer. To do that, we need to know what version the draft is based on. If not metdata.version, it needs to be _something_ to indicate the currently-published version. I think there are other use-cases for that info, as well, BTW. Publish needs to know it, so as to potentially reject an edit based on out-of-date root doc. Hmm, how about 'base-version' ?