The raw file you are viewing is a response page template. When that page is presented to the client making the request, the %MACRONAME% values are substituted and the HTML (or JSON) content returned from the web reverse proxy has that substituted text. Hint, you can further customize the messages to the user by substituting the macro into a javascript variable within the response page template, and then make logic decisions based on that client side javascript code. For example, you could catch one of the IBM error codes and translate it into saying something like "Account is locked".
More information is available on the macros within the IBM documentation.