I realize it is not "synchronized". However, I have noticed that some manufacturers refer to the ability to shift "in line" from forward to reverse as a "shuttle" shift.
As opposed to a "synchro-shuttle".
For example. The Kubota SU 4800 has a "synchro-shuttle". Low range forward to reverse without stopping, but still requiring the clutch. The Kubota
MX 5000 has the same transmission, but it's not synchronized. Low range forward to reverse is "in line" for ease of shifting. You must come to a complete stop before shifting. They refer to this as a "shuttle". I think LongAgribusiness refers to their inline, non-synchronized fwd/rev as a "shuttle" to.