Examine source code of Pixiv Toolkit

{
  "background": {
    "scripts": [
      "lib/pouchdb.min.js",
      "lib/pouchdb.find.min.js",
      "backgrounds/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "__MSG_extName__",
    "default_popup": "popup_page/index.html"
  },
  "short_name": "PTK",
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "default_locale": "en",
  "description": "__MSG_extDescription__",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "storage",
    "unlimitedStorage",
    "*://*.pixiv.net/*",
    "*://*.pximg.net/*",
    "*://*.techorus-cdn.com/*",
    "*://*.fanbox.cc/*"
  ],
  "optional_permissions": [
    "downloads"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.pixiv.net/*"
      ],
      "css": [
        "content_scripts/static/css/app.css"
      ],
      "js": [
        "lib/global.js",
        "lib/vue.min.js",
        "lib/vue-i18n.min.js",
        "lib/locales.js",
        "lib/handlebars-latest.js",
        "lib/jszip/jszip.js",
        "lib/jszip/jszip-utils.min.js",
        "lib/js-epub-maker/js-epub-maker.js",
        "lib/gifjs/gif.js",
        "lib/whammy.js",
        "content_scripts/app.js"
      ]
    },
    {
      "matches": [
        "*://*.fanbox.cc/*"
      ],
      "css": [
        "content_scripts/static/css/fanbox-cs.css"
      ],
      "js": [
        "lib/global.js",
        "lib/vue.min.js",
        "lib/vue-i18n.min.js",
        "lib/locales.js",
        "lib/jszip/jszip.js",
        "lib/jszip/jszip-utils.min.js",
        "content_scripts/fanbox-cs.js"
      ]
    }
  ],
  "version": "4.9.0",
  "options_ui": {
    "page": "options_page/index.html",
    "open_in_tab": true
  }
}