A while back (six months or so?), Hive-Engine was hacked and reportedly a bunch of HIVE (or was it SWAP.HIVE?) along with Bitcoin was taken. IIRC, a week or so later the HIVE was returned. But I don’t recall anything about the Bitcoin being returned. Did that happen and I just missed it?
Also, SWAP.BTC notes that it’s “BITCOIN backed by the steem-engine team” but what exactly does that mean? Is there any actual Bitcoin backing it?
In theory, it's supposed to be because you are technically allowed to withdraw that as BTC into your wallet.