Online documentation missing info

In the past, the online documentation gave examples on how to customize the RRDTool step and RRAs via the config.php file. It included setting for $config['rrd']['step'] and $config['rrd']['rra']. I had modified these settings to keep 5 minute intervals for 2 years. Everything is still working however i wanted to make a change and needed to refer to the examples. I can no-longer find any reference to these settings in the documentation... hopefully this isn't a sign of this feature being removed... Help

Thanks!