nostr:npub1namj0ypwfctycz0lx78sdczy70fqxs76xuegzjlgmczpdrnlsvwsptl3t5 You appear to be able to enable ECH on Firefox, only. https://blog.mozilla.org/security/2021/01/07/encrypted-client-hello-the-future-of-esni-in-firefox/ has the detail. (Source of this graphic: https://www.tunnelbear.com/blog/introducing-encrypted-client-hello-ech/ )

https://assets.bne.social/media_attachments/files/111/057/574/866/358/123/original/d6e341fe133c9141.png