Thanks for pinging me here @jill
AFAIK cc2olx supports a selected set of content type and if there is a content type present that is not supported by cc2olx it gives out empty XML and also raises warnings in the logs.
There were plans to add more content types and clean the error parsing mechanism but I guess other work took priority over it. The eventual goal of this repo was to be merged with course import flow so that the users could directly upload the course in Studio.
Right now it is far away in terms of features and supported content type. Let me know if you have more questions about it.
probably @0x29a can add more information about cc2olx. 