https://www.blocktrail.com/BTC/block/000000000000000001a04ace6390273bcecbe2b07603853987306c2c72723042
The weird part is that it is signalling so many things at once,
Stay tuned for a follow-up list. Note: It has also started signalling Segwit on LTC less than 1 hour ago.
According to the coinbase, they may be also signalling for BU.