Yes - they mean the actual mechanism of the lock. However, it wasn't clear in the text whether it was the ignition lock or the door lock. I've not looked at my car to see if there is a difference.

I do know that the external locks are engineered differently - they have to resist extenal penetration by rain, road salt, fuel, diesel, mud etc. This is usually accomplished by a flap and a seal near the outside of the lock barrel.

Conversely the steering column lock has to detect when the key has been placed inside, so that the interior lights, the alarm and the "key left inside your car" warning signal etc are correctly activated. I can imagine this also involves a flap, but this time without the all weather seals. It could also of course involve a contact at the far end of the barrel where the tip of the key pushes against a switch mechanism.

I'm not an expert on this aspect of car design, I'm just relaying what I read on the UK based website. WD40 makes sense as long as you don't use too much.

As an aside, the style of the X type key (stainless steel shaft with angular plungers) is common to all European Fords and is much more robust than the crappy conventional style we get here in the USA (they don't bend for a start). The keys and locks are made in Germany by Kiekert and have been around since the late 1980's and are very reliable. So I'm surprised that a Jaguar would suffer from any failure mechanism linked to the locks.