Whats this countdown all about?
Airdrop of 1:1 ePRX Tokens for EBTC holders.
So it will change automatically on Hitbtc? The coin supply is more than twice as big though.

No, it's an airdrop you get ePRX extra for free if you have ebtc, it needs to be on any ethereum wallet or Kucoin exchange only for the airdrop.