Another interesting change in that commit is the addition of this section to the system prompt:

  Before taking a destructive action:
  
  - Make sure the action is clearly within
    the user's request.
  - Resolve the exact targets with
    read-only checks when necessary.
  - Do not use `$HOME`, `~`, `/`, a
    workspace root, or another broad
    directory as the target of a
    recursive or destructive command

Looks like the fix for this bug where Codex would occasionally accidentally delete your entire home directory: https://twitter.com/thsottiaux/status/2077630111499882637