Examine source code of Web Developer Form Filler

{
  "content_scripts": [
    {
      "js": [
        "javascripts/jquery-3.3.1.min.js",
        "javascripts/deserialize.js",
        "javascripts/content_script.js",
        "javascripts/mousetrap.min.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*",
        "file:///*"
      ],
      "run_at": "document_start"
    }
  ],
  "name": "Web Developer Form Filler",
  "version": "1.3.0",
  "icons": {
    "16": "images/16.png",
    "48": "images/48.png",
    "128": "images/128.png"
  },
  "description": "This extension is used by developers to make it easy to save and fill forms for use in submission testing and validation.",
  "homepage_url": "https://github.com/etbusch/web-developer-form-filler-ext",
  "browser_action": {
    "default_icon": "images/48.png",
    "default_title": "Web Developer Form Filler",
    "default_popup": "popup.html",
    "theme_icons": [
      {
        "light": "images/16_dark.png",
        "dark": "images/16.png",
        "size": 16
      },
      {
        "light": "images/48_dark.png",
        "dark": "images/48.png",
        "size": 48
      },
      {
        "light": "images/128_dark.png",
        "dark": "images/128.png",
        "size": 128
      }
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d354848e-5fd6-41c3-84d3-76e920aac579}",
      "strict_min_version": "53.0"
    }
  },
  "background": {
    "page": "background.html"
  },
  "permissions": [
    "tabs",
    "http://*/",
    "https://*/",
    "storage"
  ],
  "manifest_version": 2
}