A function added by the New Vegas Script Extender.
Returns a constant, an invalid array. This is used to clear up array variables when they are no longer necessary, such as when a script terminates.
As of NVSE 4.6.2, arrays defined in UDF scripts are cleaned up automatically, but those held in other scripts are not. Therefore it is essential to use Ar_Null to clear any local array variables when other scripts terminate to avoid save game bloat.
let SomeArray := Ar_Null