Examine source code of Tabster

{
  "manifest_version": 2,
  "name": "Tabster",
  "version": "2.1.1",
  "description": "Manage great amounts of windows and tabs at ease.",
  "icons": {
    "48": "icons/tabby-48.png",
    "96": "icons/tabby-96.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "contextMenus",
    "<all_urls>",
    "cookies",
    "contextualIdentities"
  ],
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/tabby-32.png",
    "default_title": "Tabster",
    "default_popup": "popup/index.html"
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+Space",
        "mac": "MacCtrl+Shift+Space"
      },
      "description": "Open Tabby, with focus on the search bar"
    },
    "last-used-window": {
      "suggested_key": {
        "default": "Ctrl+Shift+0",
        "mac": "MacCtrl+Shift+0"
      },
      "description": "Open last used window"
    }
  },
  "applications": {
    "gecko": {
      "id": "campbell_kerr@hotmail.com",
      "strict_min_version": "59.0"
    }
  }
}