Examine source code of Quick Lookup

{
  "manifest_version": 2,
  "name": "Quick Lookup",
  "version": "1.2.0",
  "description": "Select a word or phrase and open its translation by pressing a shortcut (Alt+X)",
  "homepage_url": "https://github.com/dhelmr/quick-lookup",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "storage"
  ],
  "page_action": {
    "default_icon": "icons/enabled-32.png",
    "show_matches": [
      "<all_urls>"
    ]
  },
  "options_ui": {
    "page": "settings.html"
  },
  "commands": {
    "run": {
      "suggested_key": {
        "default": "Alt+X"
      },
      "description": "Open translation"
    }
  }
}