Examine source code of RainbowTabs

{
  "manifest_version": 2,
  "name": "RainbowTabs",
  "version": "1.1.0",
  "description": "Color-code your browser tabs for visual organization (Firefox — uses Container Tabs)",
  "permissions": [
    "storage",
    "tabs",
    "contextualIdentities",
    "cookies",
    "contextMenus",
    "activeTab",
    "https://www.rainbowtabs.net/*"
  ],
  "background": {
    "scripts": [
      "sync.js",
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "RainbowTabs"
  },
  "commands": {
    "open-color-picker": {
      "suggested_key": {
        "default": "Ctrl+Shift+C"
      },
      "description": "Open color picker for active tab"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "rainbowtabs@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [],
        "disclosure": "RainbowTabs only syncs user-created auto-rule patterns to the cloud when the user explicitly enables cloud sync. No browsing data, history, or personal information is collected."
      }
    }
  }
}