Examine source code of Adless Spotify

{
  "manifest_version": 2,
  "name": "Adless Spotify",
  "version": "1.5",
  "description": "Mutes Spotify's Webplayer when advertisements are played. Requires to be calibrated",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "icons": {
    "32": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Adless Spotify - Calibration",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{62e31096-34e6-4503-8806-3d7a6004a1f4}",
      "strict_min_version": "57.0a1"
    }
  }
}