Linaro questions

Hi, I found a ROM featuring linaro, I googled it and only found out that it makes the device faster. Can someone please explain to me how does it all work? Because surely they need all the source code that Samsung hasn't released to get any noticeable performance improvements. I have also read that it is compatible only with ICS (such as ani droid) but there is a JB ROM with it:
http://forum.xda-developers.com/show....php?t=2137182

So any information about linaro and how it could influence the note would be much appreciated.