Level 33

An anonymous user has uploaded what appears to be the source code of iBoot —the iOS secure bootloader— on GitHub, and all evidence suggests the code is authentic.

A link to the source code became viral last night on Twitter, and drew Apple's attention, prompting the company to send a DMCA takedown request to GitHub to take down the repository.
iOS experts who managed to grab a copy or had a chance to analyze it said the code is from iOS 9.3, released in March 2016.

Despite being almost two-years-old, the iBoot code usually receives very few modifications from version to version, and large chunks of the code are most likely still used with modern iBoot versions.
The code's availability would allow both jailbreakers and hackers to analyze its internal structure for possible bugs they could exploit —for jailbreaking devices or installing malware.