CREATE PACKAGE my_pkg
IS
g_var NUMBER;
END;
/

FUNCTION FN_get_g_var  RETURN number
IS BEGIN
     return g_var; END
FN_get_g_var ;

CREATE VIEW myView AS
SELECT my_pkg.FN_get_g_var() FROM DUAL;

select name as variable_name, object_name as package_name, object_type
from dba_identifiers a
 where usage_context_id = 1
   and usage = 'DECLARATION'
   and type = 'VARIABLE'
start with object_type in ('PACKAGE', 'PACKAGE BODY')
connect by prior usage_id = usage_context_id
    and object_name = prior object_name
    and object_type = prior object_type