Sorry to keep bothering you.
I created the "calibre:user_metadata:#genre" field. I have entered some values for this field on some ebooks, burt I don't find the #genre entry in each ebook metadata.opf files.
Am I missing something here?
[EDITED]: Never mind: I've just found this
local reference in Calibre's Forum.
I'll try it and report back on how I fared with Librera.
Thank you all for your patience!
[INCANUS]