Examine source code of Look-Up

{
  "applications": {
    "gecko": {
      "id": "{d54785a6-5dc5-4135-8566-fc81ed290d88}",
      "strict_min_version": "48.0"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/look-up.png",
    "default_title": "Highlight a word to show meaning",
    "default_popup": "pop_up/look-up.html"
  },
  "background": {
    "scripts": [
      "look-up-background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "look-up-content.js"
      ]
    }
  ],
  "description": "Provides meaning of highlighted words",
  "developer": {
    "name": "Yeshwanth Arcot",
    "url": "https://github.com/ysharc/"
  },
  "homepage_url": "https://github.com/ysharc/look-up",
  "manifest_version": 2,
  "name": "Look-Up",
  "options_ui": {
    "page": "options/look-up-options.html",
    "open_in_tab": true
  },
  "permissions": [
    "notifications",
    "storage"
  ],
  "version": "0.3resigned1"
}