Examine source code of SoundCloud Downloader

{
  "manifest_version": 2,
  "name": "SoundCloud Downloader",
  "version": "1.15.0",
  "author": "NotTobi",
  "description": "Adds download buttons for tracks on soundcloud.com",
  "homepage_url": "https://github.com/NotTobi/soundcloud-dl",
  "icons": {
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "downloads",
    "webRequest",
    "storage",
    "webRequestBlocking",
    "*://*.soundcloud.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.soundcloud.com/*"
      ],
      "js": [
        "js/content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "options_ui": {
    "page": "settings.html"
  },
  "page_action": {
    "default_icon": {
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "96": "icons/icon-96.png",
      "128": "icons/icon-128.png"
    },
    "default_title": "Soundcloud Downloader",
    "show_matches": [
      "*://*.soundcloud.com/*"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c7a839e7-7086-4021-8176-1cfcb7f169ce}"
    }
  }
}