Examine source code of Save all files

{
  "manifest_version": 2,
  "name": "Save all files",
  "description": "Adds a context menu to save media {image, video, audio, link, selection, page} in user-defined directories relative to the default download location. Save into dynamically named directories. Rules-based download renaming and routing.",
  "version": "1.0.0",
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "info@siziflearn.ir"
    }
  },
  "developer": {
    "name": "MR Sizif",
    "url": "https://sizifart.com"
  },
  "homepage_url": "https://4zhina.com",
  "background": {
    "scripts": [
      "src/vendor/browser-polyfill.js",
      "src/vendor/content-disposition.js",
      "src/chrome-detector.js",
      "src/constants.js",
      "src/notification.js",
      "src/path.js",
      "src/download.js",
      "src/router.js",
      "src/shortcut.js",
      "src/messaging.js",
      "src/headers.js",
      "src/variable.js",
      "src/menu.js",
      "src/option.js",
      "src/index.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/content/content.js"
      ]
    }
  ],
  "permissions": [
    "<all_urls>",
    "activeTab",
    "tabs",
    "contextMenus",
    "downloads",
    "notifications",
    "storage",
    "webRequest",
    "webRequestBlocking"
  ],
  "options_ui": {
    "browser_style": true,
    "chrome_style": true,
    "page": "src/options/options.html"
  },
  "icons": {
    "48": "icons/ic_archive_black_48px.png",
    "96": "icons/ic_archive_black_96px.png",
    "128": "icons/ic_archive_black_128px.png"
  }
}