ad_partner_var_or_default varWhat it does:
Returns the specified variable for the current parter, unless it's the empty string in which case it returns the variable for the cobrandsitedefaultDefined in: /web/philip/tcl/ad-partner-defs.tcl
Source code:
set value [ad_partner_var $var] if { ![empty_string_p $value] } { return $value } return [ad_partner_var $var "" 0 [ad_parameter CookieDefault partner]]