What to do with the amount not airdropped has not been determined yet as far as I know. The appeals for the accounts that did not get airdrops have not been completed.

I do believe that when the airdrops are complete it will probably be left in the dhf fund for future development. Some of it may be burned. 🤷‍♀

The original allocation of the steemit inc ninja mine was for development. I do not see it being powered up though.