Examine source code of Dark mode / night reader

{
  "name": "Dark mode / night reader",
  "description": "Inverts page colors, showing white text on a dark background",
  "version": "2018.12.8.1resigned1",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "match_about_blank": true,
      "css": [
        "style.css"
      ],
      "js": [
        "load.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "Darken",
    "default_icon": {
      "19": "icon-19.png",
      "38": "icon-38.png"
    }
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "options_page": "options.html",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "@darken"
    }
  }
}