I assume this is a UK bike.
If so, it's the "atmospheric temperature sensor" aka the switch used for the carb heaters. Here in Canada we don't have the heaters in the carbs (we do have the holes for the heaters) and we don't have this sensor switch. To my knowledge there is no electronic air fuel mixture unit - it's call adjustment needles in the carbs.
If the carbs still have the heaters installed (you can tell by wires running into the bottoms of them) you may want to leave it. I'm not sure how prone the carbs are over there to icing up. Perhaps someone who has carb heaters can chime in.
This would have been in the OEM airbox as per this photo from the service manual.