[Typo3] how to turn off relogin?

[Bing Du]

Hi Jerome,

Jerome Vandenende wrote:

> You can change it in Configuration Tool> 
> $TYPO3_CONF_VARS['BE']['sessionTimeout'] = 3600;

Thanks much for the help.

Now I found this variable ($TYPO3_CONF_VARS['BE']['sessionTimeout'] = 
3600;) in the BE.  It says "Now , copy/paste this value into the 
configuration file where you can set it. This is all you can do from 
here...".  Which configuration is it in?  I don't see it in 
typo3conf/localconf.php file.

Bing