In your case, /classifications/
is of Kind
taxonomyTerm
so you would need to specify the following as well:
[outputs]
taxonomyTerm = ["json"]
…However even having added that, I still could not see public/en/classifications/index.json
being generated.
So I got curious about this and did some more testing, and the only way (so far) that I have been able to generate that is by adding content/en/classifications/_index.md
(as per docs example on custom taxonomy metadata) and specifying the following in its front matter:
---
title: Classifications
outputs:
- json
---
Not sure if this is intended behaviour.