OWNER) are the same as those in
Each column owned by the user that has an IS JSON check constraint in an AND condition appears in this view. This view enables a user to find all the JSON columns that he or she owns.
For example, if a check constraint combines the IS JSON condition with another condition using logical condition OR, then the column is not listed in this view. In this case, it is not certain that the data in the column is JSON data. For example, the following constraint does not ensure that the data in column jcol is JSON data:
jcol is json OR length(jcol) < 1000