This is a list of variables that are always implicitly assigned
to the template engine. This is handy for making global
variables or server variables available to all templates
without having to manually assign them. Each element in the
$global_assign should be either a name of the global variable,
or a key/value pair, where the key is the name of the global
array and the value is the array of variables to be assigned
from that global array. $SCRIPT_NAME is globally assigned by
default from $HTTP_SERVER_VARS.
Technical Note: Server variables can be accessed through the
$smarty variable, such as {$smarty.server.SCRIPT_NAME}. See the
section on the
$smarty variable.