Quick newsflash: Bitcoin Association Switzerland kicks off the DeFi ecosystem on Tezos with a Bitcoin-backed stablecoin. tzBTZ will be usable in Tezos smartcontracts.   

"tzBTC brings the liquidity and battle-tested brand of Bitcoin (BTC) into the Tezos ecosystem, enabling BTC-backed use-cases on Tezos. Developers on Tezos can use tzBTC to enable novel financial applications on the Tezos blockchain." 

Liquidity provider Woorton offers tzBTC tradingpairs for 20+ currencies. TzBTC is also trade-able on Sygnum, Taurus, Bity, and Bitcoin Suisse. 

tzBTC is supported on Ledger through the tzbtc-client. "A command tool specifically allowing the interaction with a Ledger hardware device for the purpose of tzBTC." At the same time Airgap adds support for the Tezos FA 1.2 standard and tzBTC.    CamlCase announces ztBTC support on Dexter soon.   

BakingBad, launched the ztBTC blockchain explorer almost instantly.