Examine source code of My Website Dimmer

{
  "manifest_version": 2,
  "name": "My Website Dimmer",
  "homepage_url": "https://www.mywebsitedimmer.com/",
  "description": "Inverted display mode for less eye strain in dark or dim lighting & search box to yahoo",
  "background": {
    "scripts": [
      "js/underscore-min.js",
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "images/bd-16.png",
      "32": "images/bd-32.png",
      "48": "images/bd-48.png",
      "128": "images/bd-128.png"
    },
    "default_title": "Toggle night mode"
  },
  "content_scripts": [
    {
      "all_frames": true,
      "js": [
        "js/content_script_start.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_start"
    },
    {
      "all_frames": true,
      "js": [
        "js/content_script_idle.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "16": "images/bd-16.png",
    "32": "images/bd-32.png",
    "48": "images/bd-48.png",
    "128": "images/bd-128.png"
  },
  "permissions": [
    "declarativeContent",
    "storage",
    "contextMenus",
    "activeTab",
    "tabs",
    "https://www.bensendigital.com/mywebsitedimmer/*",
    "https://*.yahoo.com/*"
  ],
  "version": "1.2",
  "chrome_url_overrides": {
    "newtab": "landing.html"
  }
}