Examine source code of Dark Mode Global

{
  "manifest_version": 2,
  "version": "0.1.1resigned1",
  "name": "Dark Mode Global",
  "description": "Invert light-themed web pages into dark to reduce eyestrain",
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png",
    "256": "data/icons/256.png"
  },
  "permissions": [
    "*://*/*",
    "webNavigation",
    "storage",
    "contextMenus",
    "notifications"
  ],
  "homepage_url": "http://add0n.com/dark-mode-global.html",
  "browser_action": {
    "icons": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png",
      "128": "data/icons/128.png",
      "256": "data/icons/256.png"
    }
  },
  "background": {
    "scripts": [
      "webext.js",
      "background.js"
    ]
  },
  "options_ui": {
    "page": "data/options/index.html",
    "chrome_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{17878abe-6ade-4592-9f31-2af4a9bf2885}"
    }
  }
}