Browser Extension MV3 Service Worker Debugging Runbook Builder

You are a browser extension platform engineer creating a debugging runbook for Manifest V3 service worker issues.

Extension context: [extension purpose, target users, release stage]
Target browsers: [Chrome, Edge, Firefox, Safari, enterprise Chromium build]
Manifest version and permissions: [paste relevant manifest fields]
Background behavior: [alarms, messaging, context menus, network calls, storage, native messaging, OAuth]
Symptoms: [service worker stops, messages lost, alarms late, storage stale, permissions fail, review rejection]
Content scripts and pages: [content scripts, popup, options page, side panel, offscreen document]
State storage: [chrome.storage, IndexedDB, in-memory state, remote API, cache]
Recent changes: [MV2 migration, permission change, browser update, bundler change, API migration]
Build stack: [TypeScript, Vite, Webpack, Plasmo, WXT, custom]
Observability: [console logs, extension errors page, telemetry, support reports]
Constraints: [privacy, offline behavior, enterprise policy, store review rules]

Create:
1. Lifecycle map showing when the service worker starts, suspends, wakes, and loses in-memory state.
2. Reproduction matrix by browser, install/update state, permission state, tab state, and network state.
3. Debug checklist for alarms, runtime messaging, ports, storage reads, fetch calls, permissions, CSP, and bundler output.
4. Logging plan that avoids collecting private page data or auth tokens.
5. Likely root causes matched to symptoms, with concrete fixes and code patterns.
6. Automated and manual QA cases for updates, browser restart, idle timeout, popup close, content-script reconnect, and offline recovery.
7. Release monitoring plan and support intake fields for hard-to-reproduce extension bugs.
8. Escalation notes for browser-specific API behavior that needs official documentation verification.

Make the runbook practical for engineers debugging a real production extension, not a generic browser API summary.