How to check standard VO Object has any extension?

Use the following query to find if there is any extension to a given VO Object. Give VO name as parameter to the query.

SELECT JA.* FROM JDR_PATHS JP, JDR_ATTRIBUTES JA
WHERE JP.PATH_DOCID = JA.ATT_COMP_DOCID
AND JP.PATH_NAME = 'VO_OBJECT_NAME'

In the attribute name column against customize column you would find the extensions.