Examine source code of SoundStamps

{
  "manifest_version": 2,
  "name": "SoundStamps",
  "version": "1.0",
  "description": "Bookmark timestamps of music you listen on SoundCloud",
  "browser_action": {
    "default_icon": "assets/icons/sound_icon.svg",
    "default_title": "SoundStamps",
    "default_popup": "build/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "mateuscelio10@hotmail.com"
    }
  },
  "permissions": [
    "activeTab",
    "notifications",
    "storage"
  ],
  "background": {
    "scripts": [
      "build/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://soundcloud.com/*"
      ],
      "js": [
        "build/content.js"
      ]
    }
  ]
}