Ton connect core functionality is based on what is already published as darttonconnect.
This implementation will follow a new direction from now on and it is going to be developed as a part of ton package.
TON Connect 2.0 is a communication protocol between wallets and apps in TON. Using TonConnect allows you to create authorization for applications, as well as send transactions within applications, confirming them using wallets integrated with TonConnect.
Overview in the TON documentation, a simple example of using TON Connect.
This SDK for Dart will allow you to use Ton Connect for cross-platform applications on Flutter.