There was (not sure if it is still available) an airdrop of Stellar Lumens for BTC holders. Claiming Bitcore requires providing BTC address and signing a message in your BTC wallet. It is available until November 2nd.
So it similar to to Byteball? I got some Byteballs by signing and verifying messages. It was a waste of time, I was unlucky to bother with this by the time they did the 180 on the rewards to try to stop dumping. Don't expect much, something along the lines of 10 bucks wort of 10 BTC signed, or at least it was this shit the last time I signed them. Not sure what % they are giving to holders now, they raised it apparently, but I didn't even bother opening my wallet since then.