I think Brendan’s mod came out ~2015 and Sa-Matras came out around 2013 which, itself is an adaptation of another mod. Please correct me if I am wrong. Not to say any of this is really new or original. As I recall there is an Arma 2 wasteland mod that came out before Arma 3: https://forums.bohemia.net/forums/topic/134450-arma2ru-waste...

Brendan's original mod was a fork of DayZ for Arma2 and came out roughly the same time as the Arma2 wasteland mod.