What is the difference between "citation-key" and "id" in CSL YAML export?

[allefeld]

When I export to CSL YAML, the entries always start with a field id, and later comes a field citation-key. E.g.

- id: ernst2004
  …
  citation-key: ernst2004
  …

The two keys seem to be usually, but not always, the same.

My questions:

• Why are there two similar (identical?) keys in the YAML output, and what is their difference?
• Which of the two should be used for citation e.g. in Pandoc Markdown?
• Could the one not used for citation be omitted from the export?

[retorquere]

The two keys seem to be usually, but not always, the same.

They ought to be the same, always.

My questions:

• Why are there two similar (identical?) keys in the YAML output, and what is their difference?

Different purposes. citation-key is a CSL variable that can be used in rendered output, in principle (although I don't know any style which does). id is how you address the item when citing in eg pandoc.

• Which of the two should be used for citation e.g. in Pandoc Markdown?

id.

• Could the one not used for citation be omitted from the export?

Yes, as can any CSL field, by adding it to skipfields in the preferences.

[allefeld]

Thanks!