Bounty Hunter is a mod that forces players to kill for income. The mass and energy buildings are removed and instead players must kill enemy units and structures to increase their mass and energy rates.
The income you receive is based on the Mass/Energy Values Killed, on top of a starting bonus of 10x normal rate. You can also Reclaim objects to top up your income.
It's designed as the antidote to a hard day's resourcing.