Check out Sentinel Chains, a new sidechain proposal that allows two-way pegging of funds WITHOUT modifying Bitcoin Core. Hint: It uses Nostr as a signaling system for peg-out consensus enforcement. Read and find out how: https://ursus.camp/bitcoin/2023/08/10/sidechains.html

P.S. It also has interesting implications for the future of Bitcoin soft forks and how they can be deployed without modifying Core.