what is bullbitcoin-mobile fr?

BULL Wallet is a self-custodial Bitcoin wallet app for mobile devices. The term "self-custodial" means the app creates and stores your private keys, the cryptographic passwords that control your Bitcoin, directly on your device. No third party, including the developers, ever holds or can access your funds. The wallet also works with the Liquid Network and the Lightning Network, two related systems designed for faster or more private Bitcoin transactions. A swap provider handles conversions between these networks. When you first set up the wallet, it creates two accounts from a single recovery phrase. The Secure Bitcoin Wallet holds funds on the main Bitcoin network. The Instant Payments Wallet holds funds on the Liquid Network for faster, cheaper transfers. Both can send and receive Lightning Network payments. The app can automatically route incoming payments to the most appropriate wallet based on the amount, though you can override this choice. You can also create multiple separate wallets and add an extra password, called a BIP39 passphrase, for additional security. The wallet includes several tools to prevent users from losing money to high fees or mistakes. It pulls fee estimates from a public dashboard rather than relying on the default Bitcoin software. If a transaction's fee seems too high relative to the amount sent, or if you try to pay a Lightning invoice from the slower Bitcoin network, the app warns you. You can also manually select specific chunks of Bitcoin to spend, label your transactions for privacy, and connect to your own private server to check your balances. Security features include an optional PIN code to open the app and secure storage for your keys. The app warns you until you successfully test your recovery phrase by typing it in, ensuring you have a working backup. You can also pair the app with hardware wallets, which are dedicated physical devices that sign transactions offline. The code is open-source, and anyone can verify that the published app matches the source code. The wallet also connects to the Bull Bitcoin exchange service, letting you buy and sell Bitcoin within the app, though this exchange feature is optional. The full README is longer than what was shown.