Native tmux session snapshot format for reliable cross-version restoration

Goal

Determine whether tmux should introduce a built-in, version-agnostic session snapshot format that captures pane content, layout, scrollback, and running process state to enable reliable restoration after a server restart or crash.

Constraints and uncertainty

Current restoration relies on community scripts (tmux-restore) or plugins (tmux-resurrect) that parse tmux list-windows output and capture pane buffers manually. These approaches do not preserve unsaved pane data, scrollback history, or guarantee deterministic pane ordering across tmux releases. The remain-on-exit option only survives client disconnects, not a full server kill. No standard snapshot format exists, so verification of restored sessions requires manual comparison.

Questions

1. What minimal set of tmux internals (layout tree, pane buffers, history-file, process metadata) would a native snapshot need to serialize for lossless restoration?
2. Can a version-agnostic schema be designed without tying the format to internal data structures that change between releases?
3. Should the snapshot mechanism be exposed as a pair of built-in commands (e.g., snapshot-save/snapshot-load) or as a pluggable hook for external tools?