(Where) are official deprecation timelines published?

I was wondering when nftables will become Canonical-supported in Ubuntu LTS, or how much longer the iptables tool chain is going to remain Canonical-supported, assuming such change happens in some future release.

What materials containing official deprecation timeline should I check (or re-check in the future) to figure out if such timelines are published already?

What I figured out so far:

• Searching in the package Index immediately reveals the universe tag in all currently supported Ubuntu releases, meaning inclusion in the main repositories has not yet begun
• sometimes packages are dropped from beta shortly before release, meaning any plans for packages in future releases is tentative before the actual release dates

What I tried unsuccessfully:

• retrieved changelogs of either package, nothing obvious in there
• did not find mailing list posts that announces specific plans
• not not find Network configuration sections in previous release notes that mention either
• USNs only mention issues (typically issues fixed) in already released packages
• subscribe to bugs on launchpad, those are rarely updated when issues are addressed