Examine source code of Wordstore

{
  "manifest_version": 2,
  "name": "Wordstore",
  "version": "2.4",
  "default_locale": "en",
  "description": "Add words on a page to a word list, to be used for various purposes.",
  "author": "Christopher Snow",
  "homepage_url": "https://github.com/Christofosho/Wordstore",
  "icons": {
    "48": "icons/wordstore-48.png"
  },
  "browser_action": {
    "default_icon": "icons/wordstore-32.png",
    "default_title": "Wordstore",
    "default_popup": "popup/wordstore.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "contextMenus"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e8990873-ad1c-4576-989d-8a2a4486f00f}"
    }
  }
}