Environments are ranked — dev, staging, production — and production can be locked against merges the moment it matters most: right before launch.
Your environments — typically dev, staging, production — are ordered by rank. Every open change request tied to an environment shows up against it, so it's visible at a glance what's queued for staging versus what's still only proposed for dev.
Freezing an environment stops any change request targeting it from being merged — instantly, without touching anything already live. Proposals and approvals keep moving; they just queue behind the freeze until someone with the right role lifts it. It's the one lever that matters during a launch window or an incident.
Beyond the per-environment toggle, the Freeze window panel shows every environment's frozen state in one list — useful the moment you need to lock down more than one environment at once, without hunting across separate screens to do it.
Promoting copies an environment's effective values forward to the next one in rank — the way values actually resolved, not a manual retyping of what you think staging should look like. Every promotion is its own ledger entry too, so "what did production actually get from that promotion" is never a reconstruction exercise.