What is 'de minimis' trade loophole closed by Trump?

US President Donald Trump shut "de minimis" exemption on import tariffs, a trade loophole Shein, Temu, AliExpress used to ship packages duty-free from China. 'De minimis', legal term for matters of little importance, was US waiver of standard customs, tariffs on imported items worth under $800. These packages are now subject to either 30% of value or $25 per item.