If you drive around in EU then be aware that the law is different depending on the country. Schweiz for example do not allow to use or sell databases that has the location of speed cameras. In Germany you are not allowed to use apps that warn you of it. You are also not allowed to use your car lights to warn other drivers, but you can use hand signals. They are however allowed in other places like Belgium, Neitherlands and Spain.
As someone that lives and works on the DACH region, you just have to listen to German and Swiss radios, they do tend to point out radar spots, regardless of those laws, so dunno how they get their permissions to do so.
Here is a list (but I can't say how accurate it is): https://lizhiguos.com/driving-aids-and-speed-camera-warnings...