Release notes: https://nyxt.atlas.engineer/article/release-3-pre-release-3.org
For Ubuntu 22.04: the .deb file depends on libssl1.1. To install it:
$ wget http://archive.ubuntu.com/ubuntu/pool/main/o/openssl/libssl1.1_1.1.0g-2ubuntu4_amd64.deb
$ sudo dpkg -i ./libssl1.1_1.1.0g-2ubuntu4_amd64.deb
To compile from source, prefer the tarball including the submodules if you don't manage the Lisp dependencies yourself.