Block contains "RSKBLOCK:Ý¿QzßýKÊwQP[9É: ÔyüN9ÝW³GÆ$", so I think that it is related to www.rsk.co. Probably Sidechains synchronization.
EDIT:
Binary hex: "52534b424c4f434b3addbf517adf8ffd4bca7751505b39c9013a0d1fd479fc4e901b39dd57b347c624"
Source: https://blockchain.info/tx/9bf8853b3a823bbfa1e54017ae11a9e1f4d08a854dcce9f24e08114f2c921182?show_adv=true