ground connection	headlight wires, suitably waterproofed for the front of the car.	more ground connections
French suspensions are so good, vibration is not a problem.		used to be illegal in many states
almost bestiality	A splice. This yellow wire is always hot, even when the ignition is off.	I suspect this was a 'repair'. I certainly hope it's not OEM.
Red is hot & black is ground, right? WRONG!!!!!!!

Ten years later, and they still haven't figured it out.   This image is from the 25GTi, model year 1987. 

The Bosch connector is to the valve that admits additional air to stabilise the idle when the motor is cold.  It has a weatherproof flexible boot that extends 2-3 cm up the wire. The boot completely encases the connector, which has a spring clip to hold it in place.  The connector is protected from the elements.

The Citroen equivalent went to the oil pressure sender.  Like the rest of the connectors on the car, it is a sleeve of hard plastic around the metal female connection.  The wire is crimped to the metal connector.  Nothing else to hold it in place.  The plastic sleeve protects the metal connector from short-circuiting, but not from the elements.  And the wire is short, so it was stretched to reach the oil pressure sender