Examine source code of Keyboard Warrior

{
  "manifest_version": 2,
  "name": "Keyboard Warrior",
  "version": "0.0.1",
  "author": "Mike Schekotov",
  "developer": {
    "name": "Mike Schekotov",
    "url": "https://twitter.com/torunar"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "keyboard-warrior@torunar.ml"
    }
  },
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "48": "/icons/icon.svg",
    "96": "/icons/icon.svg"
  },
  "browser_action": {
    "default_icon": {
      "19": "/icons/icon.svg",
      "38": "/icons/icon.svg"
    },
    "default_title": "__MSG_actionShowNavigationHelpersToolbar__"
  },
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "/background.js"
    ]
  },
  "commands": {
    "keyboard-warrior-show-navigation-helpers": {
      "suggested_key": {
        "default": "Ctrl+Shift+L"
      },
      "description": "__MSG_actionShowNavigationHelpers__"
    }
  }
}