Odd
June 13, 2019. The question is odd. The answer is one word in capitals, the TOMI field four words in lower case. Digits 4f0, 7 and 89.
One hint, a day later. The third word of the TOMI field is alphabet. And the second digit of the answer's hash is not 3. A nice way to stop people chasing the wrong idea. What do you do with a word like odd?
ACE
The source is a tweet by Pieter Wuille. The vowels sit at odd positions in the alphabet. A, C and E are the first three odd letters in a row. So the answer is ACE.
u/Randomiser posted ACE TOMI odd numbered alphabet letters. The claim confirmed at 00:05:14 UTC on June 15, about an hour after the hint.
Numbers or letters?
The author's update says the TOMI field was odd numbered alphabet numbers. The chain disagrees. ACE TOMI odd numbered alphabet letters hashes to 4f0, the posted digits, and gives the address the claim spent. The numbers version hashes to b80. Same story as block 29: typo in the post, not in the puzzle.