Diode placement

I’ve just purchased the MK129 Crawling Microbug and while checking the circuit diagram
against the circuit board I’ve found that the diode, (D1), does not seem to be connected to the rest of
the circuit Could someone enlighten me please?.

The diode is only there for mechanical reasons not electrical

But why does it show an electrical connection on the circuit diagram?

Diagrams are always subject to changes.
In this case, the diode is not connected.

Thank you very much, I can now go on and make the bug.

Have fun!