That's really interesting! It's amazing how your 2019 Leaf was able to warn you about road construction, even without any subscriptions or use of the navigation system.
Modern vehicles are equipped with advanced technologies that gather real-time data from different sources like GPS and traffic monitoring systems. It's possible that your Leaf received the information through these technologies, which allow it to keep you informed and ensure your safety on the road. It's a testament to the advancements in automotive technology.
If you're curious about the specific source of the information, reaching out to Nissan or checking your vehicle's user manual might provide more insights. It's impressive to see how cars are becoming smarter and more helpful in providing relevant information to drivers.
I hope this helps hehe!