Who is doing the custody for this LNTXBOT?

Here is the message from Signal support:
Any cryptocurrency wallets that we include support for also have to work well from within Signal. This would mean:

1. Integration is “non-custodial”: Signal does not have access to your keys or your funds; that information remains associated with your own wallet.
2. Like everything else in Signal, data is private: all your data stays in your hands rather than being visible to others.
3. Transactions are fast: like Venmo, it can only take a few seconds to send a transaction.
4. Everything works well on mobile: it can’t require downloading and scanning all ongoing transactions in order to find your own.
5. The experience is simple: in most other ways the experience should be the same as something like Venmo.
6. It can scale to hundreds of millions of people.