Do custom user fields come back when there is no value?

I am developer in Torii and I am using this end point to fetch the users - Users | Okta Developer
When a user object returns from the API there is a profile fields that contains some custom user fields.
In the case that a custom user field does not have a value, does the user field not show in the user.profile object or will it show up with the value null or an empty string " "?

No, attributes that are null will not be returned by the Users endpoint