IMO, calibre is two-way. From any file format to any other. That is _hard_ to do really good. Text is the easy part. What about tables? What about image captio

IMO, calibre is two-way. From any file format to any other. That is _hard_ to do really good. Text is the easy part. What about tables? What about image captions and footnotes? What such a project would need is one master file format from which other formats are derived. But not the other way around. Having disjoint repositories for books/software is a good idea though.