Examine source code of Spotify Desktop-ify

{
  "manifest_version": 2,
  "name": "Spotify Desktop-ify",
  "version": "1.0",
  "description": "Open Spotify URIs/web player links in the desktop app every time",
  "icons": {
    "16": "sd-ify-16.png",
    "48": "sd-ify-48.png",
    "128": "sd-ify-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://open.spotify.com/*"
  ]
}