et-al-min and et-al-use-first both have subsequent forms. et-al-use-last does not. It applies to both first and subsequent citations. I’m trying to write a footnote form of APA that a Zotero user requested for a journal. Like Chicago (full note), the full bibliography (which uses et-al-use-last="true") should be used for first citations, and a short form (which uses et-al-use-last="false") should be used on subsequent. For now, my plan is to just use et-al-use-last="false" for both forms, but would we consider adding an et-al-subsequent-use-last attribute?

Edit: Actually, I realize that the spec seems to be ambiguous on this point, and citeproc-js implements it by only applying et-al-use-last to the first (not subsequent) citations. Is that something that should be made more explicit?

I’d be reluctant to add a new attribute for something that has only ever been requested for a custom style and even that only once.
But including the current citeproc-js behavior into the specs seems fine to me.

That sounds good to me.