I KNOW THE ANSWER TO THIS!!!
E-cigarettes are regulated by the Chinese government and fall under the state tobacco monopoly. They are legal to manufacture in any flavour but only legal to sell in China in traditional cigarette flavours, i.e. tobacco and menthol. Any flavour can be exported out of China, which is why the US is full of fruit flavored vapes from China despite none of them being authorized for sale in the US by the FDA. That fruit flavoured vapes are not for sale in China is not ideal since flavours are associated with more switching away from cigarettes (harm reduction) than are tobacco/menthol vapes (yes, vaping is much less harmful than smoking, the chemistry and toxicology data are very clear about this) but this system is still better than in the US where every single product has to be arbitrarily reviewed individually and they've only approved ONE menthol vape (insanity). In China the manufacturer just notifies the state monopoly of the product and its technical specifications and as long as they meet the clearly-defined state requirements it can be sold. The US has no clear requirements which means their 'reviews' are lengthy and capricious.