Tether CEO Paolo Ardoino has announced that the company's Wallet Development Kit (WDK) is close to being fully open-sourced. The WDK is designed to facilitate the creation of self-custody wallets across various blockchains, including Ethereum, Bitcoin, TON, and Spark (Lightning Network). It will feature gasless transactions and DeFi capabilities, aiming to enable the development of 'trillions' of self-custodial wallets, providing users with 'pure freedom.' The kit will also include support for account abstraction and cross-chain messaging, with plans to extend compatibility to Solana and Tron in the future.