Thanks! Is this where you would access the spark plugs?They are all cosmetic covers, on a Diesel they may make a few % reduction in the noise level but that’s it, the petrol engine is far quieter by nature.
You are far better off without a cover, if there is a leak etc you’ll see it. It’s one of the first things I remove and leave off when I buy a car.
Regarding what the parts are, that’s a bigger topic and unless you are going to maintain it I wouldn’t be concerned.
Nothing to worry about.