Anyone know what 'natural flavours' means on label packaging?

These words appear on almost all food labels these days, but they are kind of meaningless. Take something like those flavoured waters, "ingredients: water, flavour". They taste amazing, there's definitely a bunch of 'stuff' in there, but they don't tell us what it is on the label?

I thought we used to have number codes for additives and what-not that they had to disclose so we knew what was in it. Did the food labelling laws change somehow? Or are these new additives something different which can just hide behind the word 'flavour'? Genuinely curious if anyone has some idea, there doesn't seem to be any explanations on the food standards website...