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.
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 view our other knowledge base articles or contact a support team member via the chat button.