Calibre

 Calibre  is a free and open source e-book and document library management application.

Development for the project occurs on GitHub at https://github.com/kovidgoyal/calibre.

Calibre offers a Goodreads plugin that can be used to sync most of one's reading and library data from that silo to Calibre. This is a relatively user-friendly way to effect export of one's data from the Goodreads silo.