Identify the format and title boundary
Jellyfin identifies OPF sidecars named content.opf or metadata.opf and ComicInfo.xml for relevant book metadata workflows, alongside format-specific embedded metadata. First identify what kind of book file you have and which title-level folder it belongs to. Do not assume that an unrelated sidecar found elsewhere in a directory applies to every file below it.
Compare the intended identity
For a handbook you authored, record its title, author and edition, then compare those values with the supported metadata file you intend to use. Preserve the previous sidecar and the original publication file. An audio edition and a revised written edition may need different labels even if they share an author.
Change one input on a sample and inspect the resulting server item. Review the selected cover as a separate field. A new picture does not establish that the author or edition is correct.
Confirm the reading task afterward
Open the item in the intended client after the metadata review. Better catalogue information does not guarantee reader support for the file format. Keep the metadata change record separate from the client compatibility result so future maintenance can diagnose either problem without undoing an unrelated improvement.
Questions answered
Can I reuse a movie NFO convention for every book?
No. Follow the documented metadata route for the actual book format.
Does correcting the author guarantee the file will open?
No. Identity and client reading support are separate checks.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.