Examine source code of Skip Unloaded Tabs (Zen)

{
  "manifest_version": 2,
  "name": "Skip Unloaded Tabs (Zen)",
  "version": "1.0.0",
  "description": "Switch to next/previous loaded tab and skip discarded (unloaded) tabs.",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "commands": {
    "next-loaded-tab": {
      "description": "Go to next loaded tab (skip discarded)",
      "suggested_key": {
        "default": "Ctrl+Shift+Up",
        "windows": "Ctrl+Shift+Up",
        "mac": "Ctrl+Shift+Up"
      }
    },
    "prev-loaded-tab": {
      "description": "Go to previous loaded tab (skip discarded)",
      "suggested_key": {
        "default": "Ctrl+Shift+Down",
        "windows": "Ctrl+Shift+Down",
        "mac": "Ctrl+Shift+Down"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "zen-skip-unloaded@example.com",
      "strict_min_version": "109.0"
    }
  }
}