TL;DR: At bitcoin core’s (BTC) present price, more than $350,000 worth of a donated bounty remains unpaid, going back to 2013 when it was first proposed by BTC developer Gregory Maxwell. He’d laid out terms for a privacy project called CoinJoin. Days after, claims to the bounty began to made and continued for some time. The topic reappeared as a point of contention recently with Maxwell openly refusing to sign a transaction for a potential claimant.