This policy setting allows you to specify the maximum limit of how much data in kilobytes (KB) the web service shim can return ...

This policy setting allows you to specify the maximum  limit of how much data in kilobytes (KB) the web service shim can return per call.  This maximum value is enforced for applications including those that do not respect the default.  If you enable this policy setting, you may specify the maximum limit of data in kilobytes the web service shim can return per call.If you disable or do not configure this policy setting, no maximum limit will be enforced.