LUNC DAO burn LUNC from their earning in LUNA staking. They burn LUNC daily and the number of LUNC burned depends on how much earning they get from their LUNA staking pool. https://twitter.com/LUNCDAO/status/1531396601192792065
It is good move from community and if it expands more, LUNC will get good support and their total supply will reduce. It is worth to note I don't promote the validator or the DEX, use their service with risk.