How are conditional fields added/removed in the middle of a set of questions?

When I have a question like `feature_x` as step 2 in the a list of questions how can I make that conditional?

For example in https://github.com/plone/cookieplone-templates/tree/unify-sub-project-settings the questions `volto_version` and `frontend_addon_name` always asked.

I tried changing the format of a question to `computed` in the `if-then`-block to hide it conditionally but it still showed up.