FirstAid
First Aid is a minecraft mod that changes the vanilla health system to be split up into different parts. Armor is only taken into consideration for the part that is currently being damaged, e.g. when you hurt your foot, the armor in the foot slot will be damage. It also introduces debuffs to make your life harder. These can be constant (as long as you don't heal your body) or on hit.
Licensing
First Aid is primary licensed under the GPL version 3 as in LICENSE.
However, there is one exception: The API package is licensed under the LGPLv2.1 as in API_LICENSE
Third Party
This project currently uses the heartbeat sound from http://soundbible.com/2162-Human-Heartbeat.html. It is licensed under the Attribution 3.0 license. Special thanks!