I see. But I don't know why we would only take mapped IDs into account. I mean - files are there on purpose (and only temporarily) and these should be processed. Some background info: service URIs reside indeed in the concordance file, that is as a relation between their URLs location and their uuid. But they are not stored as their URLs because these might make problems with the filesystem. Instead, they are stored as their uuid. However, this should only be of importance for internal data wrangling and not an issue for data converting, I think.
So I would propose to remove the whole "idMap" and its subsequent use in NtToEs .