I’d love to know the answer to this question too!

Fixtures designed and sourced from China will most likely not have a UL certification. Most of them contain a mark of CE compliance, which is for the European Union and does not require safety certification by a 3rd party or to comply with extensive safety and manufacturing standards and codes as does a UL process of certification. And, manufacturing in China is still like the wild west, where the sticker may say anything they want, CE, UL, or some other "official" sounding acronym, but doesn't necessarily mean anything. It is hard to decipher what is legitimate, unless you know you have a U.S. company backing a product, because unlike many other countries, in the U.S. a company can be held liable for their product. And these standards are not just whether a fixture may spark or overheat, but other concerns like how much lead or formaldehyde is contained in the materials.

Note that fixtures designed in the U.S., but manufactured in China, would still have to follow UL guidelines and procedures to obtain their UL certification. However, most of these fixtures would not be selling on Alibaba. You may find on their website exact or similar products to expensive ones in the U.S., but the factory owner might very well be using the same tooling or parts as they make for a U.S.-market company, but selling off-hand in the Chinese market for much cheaper because they don't have the overhead (read: safety regulations, red tape, and financial heirarchy) or substitute lesser materials.

You will also find that CE-listed Edison-socket fixtures are made for certain European-sized 'bulbs,' which are compatible with similar U.S.-sized 'bulbs,' but just slightly different to be bothersome.