see ==>>
http://idpf.org/epub/20/spec/OPF_2.0...#Section2.2.13 and or
http://dublincore.org/documents/2012...terms-relation
!. Are there any plans to make the element <relation> available in Calibre ?
2. If the answer to 1 is Yes, then when and what for ?
3. If the answer to 2 is No, then could it be implemented as the means via which links to "supplementary material" are provided, as that seems to be its intended purpose.
Then I could have a links to
- a web page containing explanatory notes and discussion,
- the Wikipedia entry for the book,
- a local file where I've written a critical essay about the 'book'
- to another book in a Calibre Library (eg Brave New World to The Tempest)
- etc etc
BR