Car manufacturers have ISO standards for symbols/icons on controls: https://cdn.standards.iteh.ai/samples/68409/6480e873c14b4e56...
One of the pain points that CarPlay and Android Auto solve for is that any car I rent or buy has the same media controls and all of my presets. When I travel for work, I try to always pick a rental vehicle that is compatible with my phone in order to reduce cognitive load of learning a new vehicle's unique controls.