ECH (encrypted client hello) is going or get enabled by default (already existed in a hidden setting) with version 118.
This page about the version explains a bit better ECH https://support.mozilla.org/fr/kb/understand-encrypted-client-hello
Tho it is still a bit confusing.
From what I understand there is the DNS query > the dns servers sends back an IP. This DNS query can be encrypted with DoH (or DoT?, it seems only DoH from the post).
Then there is a handshake with the website where the website informations can be leaked, and that can be encrypted by ECH (if the website supports it).
Then after that there is a tls connexion established between the website and the user.
The part where I’m confused is : can ECH be used without DoH? If yes that would mean that I can use a DoH capable software and not have to configure it into Firefox? (ex: Nextdns + yogadns)
No, DoH (DNS-over-HTTPS). I’d also previously set up a DoT proxy for use on my phone (since Android only supports DoT) but I decided to do something else for that.