While I'm at it breaking compatibility in favour of usability, I might also kill the reuse of the field name "id" to refer to every different kind of ID. clusterId on a Cluster, refId on a Cite because it points to a Reference. Then you won't have so many accidents like earlier in this issue.
Originally posted by @cormacrelf in https://github.com/zotero/citeproc-rs/issues/117#issuecomment-871621702