Thanks for the reply but not able to get those points. I could see below code on said page but not select query.
protected void UniGrid_OnBeforeDataReload()
    {
        // Generate where condition
        string where = String.Format("DocumentPageTemplateID = {0} OR NodeTemplateID = {0} OR NodeWireframeTemplateID = {0}", PageTemplateID);
    where = SqlHelper.AddWhereCondition(where, filterDocuments.WhereCondition);
    docElem.UniGrid.WhereCondition = SqlHelper.AddWhereCondition(docElem.UniGrid.WhereCondition, where);
}
protected void UniGrid_OnAfterDataReload()
{
    // Filter data by permissions
    DataSet ds = docElem.UniGrid.GridView.DataSource as DataSet;
    ds = TreeSecurityProvider.FilterDataSetByPermissions(ds, NodePermissionsEnum.Read, currentUser);
    plcFilter.Visible = docElem.UniGrid.DisplayExternalFilter(filterDocuments.FilterIsSet);
}
Also, not able to navigate Modules>Design>User Interface>Expand Development-Page templates-Edit page template-Pages .