// use this timezone to display date/time
$rcmail_config['timezone'] = 1;
Does this mean that timezone 1 is going to be used as default? So can we have a list of avaliable timezones with their numbers? :D
I think, this "number of the timezone" is the difference between GMT and your timezone. It's 1 because the project is located in Switzerland (timezone GMT +1)
So, if you're in New York, your timezone would be "-6" ;)