What is ACE 3?
ACE3 is a joint effort by the teams behind ACE2, AGM and CSE to improve the realism and authenticity of Arma 3.
The project is entirely open-source and all contributions are welcome. Feel free to maintain your own custom version, so long as the changes you make are open to the public in accordance with the GNU General Public License (GPLv2).
The mod is built modularly, so almost any included PBO can be easily removed from the configuration. This way, a team can maintain its own tailored version of ACE3 by simply excluding any components they don't need, or those possibly in conflict with other mods. Modules themselves, e.g. the medical system, also include various customization options, allowing mission designers to tweak the overall experience.