Examine source code of OpenSync

{
  "manifest_version": 2,
  "name": "OpenSync",
  "version": "1.2.6",
  "description": "Watch videos together - Sync playback across devices",
  "browser_specific_settings": {
    "gecko": {
      "id": "opensync@example.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "author": "OpenSync Team",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "alarms",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon-48.png"
    },
    "default_title": "OpenSync",
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "include_globs": [
        "*://*/*",
        "file:///*"
      ],
      "js": [
        "lib/protocol.js",
        "content/platformControllers.js",
        "content/videoController.js",
        "content/websocketClient.js",
        "content/overlay.js",
        "content/content.js"
      ],
      "css": [
        "content/overlay.css"
      ],
      "all_frames": true,
      "match_about_blank": true,
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    "icons/*",
    "content/overlay.css"
  ]
}