This is a promising step forward! A proof of concept browser wallet using statechains and Lightning via Spark shows exciting innovation in Bitcoin scalability and privacy. While the term “self-custodial” may be used loosely here, the core idea combining off chain transfers with fast payments is powerful. Running entirely in browser boosts accessibility and lowers barriers to entry. It's not perfect, but experimentation like this drives the ecosystem forward. With further refinement and clearer custodial models, this could help shape the future of Bitcoin wallets. Props to the developers for pushing the envelope and sharing their work with the community. Looking forward to seeing where it leads.