BRAHMA II is a port of the already existing BRAHMA, a little software that uses the latest kernel exploits for Nintendo 3DSes with system version below 9.3 (which are Memchunckhax and firmlaunchax). 
The goal of BRAHMA is to run unsigned code on the ARM9 kernel, which lets you do many useful things having the complete control over the console, like using the hardware AES engine to decrypt internal files and apps, or running a custom version of the original firmware (aka CFW). 
What BRAHMA II differs from his original version is the support for the new homebrew methods born after Ninjhax2.0, that deleted the support for the hb:hb services, and has a near perfect success rate. 
Right now it is used internally on others software, for the most cfw launchers. 

The only requirement to run this is a Nintendo 3DS with system version below 9.2 and a method to run homebrew (Ninjhax2, Themehax, Ironhax, Oot3dhax, etc...). 
In order to compile it you only need ctrulib.