Having built a tool in this space, I enjoy seeing all the Calibre alternatives that have been coming out in the last few years! It's fascinating to see the specific wants that people have.

Bookshelf, for example -- what possesses someone to make an ebook library that _only works on object storage_? Is this a weekend project, answering the question of "what would this look like"? Or was it something the author wanted for a long time?