Hi Joseph, can't be too much help but 'Honda HA3 Delta' is a model of a Honda truck, which may have been what the unit was originally designed for. It could be that the importers tried to install this system in a Jazz as a modification but found it didn't work so disconnected it and couldn't be bothered to remove it.
You'd need to ask a specialist alarm installer if they know anything about this, but if it's been unwired there are probably 3 reasons...
1 the owner was fed up with the alarm going off; ultrasonics inside the car do this (especially if a window is left a little open).
2 The alarm unit became faulty and failed.
3 The unit was installed but was incompatible.
Hope that helps.
Let us know how you get on.
Mike (Retired radio and electronics engineer).