Goodness. Someone has figured out how to make drop in auto sears for Glock handguns, has created instructions for making them with 3D printers, and has released those instructions to the internet.
That's going to make life really interesting anywhere Glock handguns are common.
Note for the gun ignorant: "drop in auto sears for Glock handguns" translates to "parts that convert Glock handguns into full-auto machine pistols".
Free legal advice from Oralloy to anyone:
Unless you are a federally licensed machinegun manufacturer (yes, the federal government offers such licenses) 3D printing one of these parts in the US will get you 10 years in federal prison, as will merely possessing a part that someone else has 3D printed.
I'd advise not even having the 3D printing instructions on my computer without such a license. I don't know that you'd get in trouble for just that, but you never know.