Hugo’s data/ directory doesn’t need any configuration. There’s always a Data entry at the bottom of the sidebar, and it browses every .json, .yaml, .yml and .toml file under data/, nested folders included. You can create files and folders from there too, even if the directory doesn’t exist yet. New files default to YAML, with JSON and TOML a click away.
If you’ve set base_path, the browser uses that site’s data/ directory (docs/data/ for a site in docs/) and won’t let you wander outside it.
Earlier versions of Emet needed data files declared in site.yaml. If your config still has that block from back then, it’s ignored; delete it whenever you like.
For editing, renaming and deleting data files, see Data files.