Examine source code of New Tab Tweaker

{
  "manifest_version": 2,
  "name": "New Tab Tweaker",
  "version": "1.7.2resigned1",
  "author": "Raoul Harel",
  "description": "Have new tabs redirect to a specified URL or display a custom page.",
  "homepage_url": "https://github.com/rharel/webext-new-tab-tweaker",
  "icons": {
    "16": "icons/main_16.png",
    "32": "icons/main_32.png",
    "48": "icons/main_48.png",
    "64": "icons/main_64.png",
    "96": "icons/main_96.png",
    "128": "icons/main_128.png"
  },
  "applications": {
    "gecko": {
      "id": "new-tab-tweaker@rharel"
    }
  },
  "permissions": [
    "contextMenus",
    "notifications",
    "storage",
    "topSites",
    "http://localhost/*",
    "https://api.imgur.com/3/album/*",
    "https://api.imgur.com/3/gallery/*"
  ],
  "background": {
    "scripts": [
      "common/js/require.js",
      "background_scripts/main.js"
    ]
  },
  "options_ui": {
    "page": "options_ui/page.html",
    "open_in_tab": true
  },
  "chrome_url_overrides": {
    "newtab": "url_overrides/newtab/page.html"
  }
}