When Bitcoin is bridged to Avalanche®, it is represented by an ERC20 token on the Avalanche C-chain with the symbol BTC.b. The “.b” indicates that the token was bridged from the Bitcoin network, just as Avalanche Bridge™ tokens bridged from the Ethereum end in “.e”. Each BTC.b token is fully backed by a Bitcoin locked by the bridge enclave application.
The BTC.b token contract can be found on Snowtrace here, and the bridge enclave application Bitcoin address can be viewed here.
Note that sending BTC.b back is the same process but in reverse, resulting in BTC.b turning into BTC.
For a more in-depth read on how the Avalanche Bridge works, please read the following articles.
For any additional questions, please visit our knowledge base or contact a support team member via the chat button at support.avax.network.