tl;dr: Podman 6.0.0 modernizes its networking stack by transitioning from slirp4netns and iptables to Netavark, Pasta, and nftables, and adds experimental Pesto rootless port forwarding that preserves source IPs. The release also overhauls Quadlets with REST API support, improves `podman machine` with multi-provider support and a new `os update` command, revises config file handling for multi-user environments, and further tightens Docker API compatibility.