It tells you whether or not you're system is at risk (most likely it is if it has an Intel chipset made in the last 9 years).
This exposes the Intel Management Engine (a small microcomputer in the mobo chipset that manages BIOS & UEFI, and allows for remote administration) to be hijacked via a USB device. A properly configured USB device can completely own you PC in a manor undetectable to the OS since this run deep down in the silicon.
While you may feel that isn't much of a threat except to enterprise users, think again. 75% of the electronics we buy are made in CHINA. We've already seen Chinese made products that contain malware. You think someone over there (hacker or government sponsored) isn't going to start embedding nasty things in USB connected devices to PWN your mobo?
Sadly only Lenovo, so far, has released BIOS firmware updates to fix this. If you're affected, it's worth checking your mobo's downloads for an updated firmware in the coming month.
https://downloadcenter.intel.com/download/27150Affected products:
6th, 7th & 8th Generation Intel® Core™ Processor Family
Intel® Xeon® Processor E3-1200 v5 & v6 Product Family
Intel® Xeon® Processor Scalable Family
Intel® Xeon® Processor W Family
Intel® Atom® C3000 Processor Family
Apollo Lake Intel® Atom Processor E3900 series
Apollo Lake Intel® Pentium™
Celeron™ N and J series Processors
