Examine source code of Mixcloud (with) Tracklist

{
  "manifest_version": 2,
  "name": "Mixcloud (with) Tracklist",
  "version": "5.0.6",
  "description": "Display tracklists on Mixcloud",
  "icons": {
    "16": "./icons/icon16.png",
    "32": "./icons/icon32.png",
    "48": "./icons/icon48.png",
    "96": "./icons/icon96.png",
    "128": "./icons/icon128.png"
  },
  "applications": {
    "gecko": {
      "strict_min_version": "58.0",
      "id": "{e7578d39-2f21-43dc-b0ba-b8baafa287a5}"
    }
  },
  "permissions": [
    "webRequest",
    "tabs",
    "http://*.mixcloud.com/*",
    "https://*.mixcloud.com/*",
    "storage"
  ],
  "background": {
    "scripts": [
      "./background_scripts/index.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.mixcloud.com/*"
      ],
      "run_at": "document_end",
      "js": [
        "./content_script/index.js"
      ]
    }
  ],
  "browser_action": {
    "default_area": "navbar",
    "default_icon": {
      "16": "./icons/icon16.png",
      "32": "./icons/icon32.png",
      "48": "./icons/icon48.png",
      "96": "./icons/icon96.png",
      "128": "./icons/icon128.png"
    },
    "default_title": "Mixcloud (with) Tracklist",
    "default_popup": "popup/popup.html",
    "theme_icons": [
      {
        "light": "./icons/icon16-light.png",
        "dark": "./icons/icon16.png",
        "size": 16
      },
      {
        "light": "./icons/icon32-light.png",
        "dark": "./icons/icon32.png",
        "size": 32
      },
      {
        "light": "./icons/icon48-light.png",
        "dark": "./icons/icon48.png",
        "size": 48
      },
      {
        "light": "./icons/icon96-light.png",
        "dark": "./icons/icon96.png",
        "size": 96
      },
      {
        "light": "./icons/icon128-light.png",
        "dark": "./icons/icon128.png",
        "size": 128
      }
    ]
  },
  "web_accessible_resources": [
    "onboarding/onboarding-install.html",
    "onboarding/onboarding-update.html",
    "onboarding/ext-icon.png",
    "icons/icon48.png"
  ]
}