Examine source code of Spotify Mute Ads

{
  "manifest_version": 2,
  "name": "Spotify Mute Ads",
  "version": "0.0.1",
  "description": "Extension to mute Google Chrome when spotify web player plays ads",
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "images/mute16.png",
    "32": "images/mute32.png",
    "48": "images/mute64.png",
    "128": "images/mute128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.mozilla.org/*"
      ],
      "js": []
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{60607615-a758-4781-a914-f12409fa41ba}"
    }
  }
}