Examine source code of Spotify-Focus

{
  "manifest_version": 2,
  "name": "Spotify-Focus",
  "version": "1.0",
  "description": "Removes focus from the play button after clicking it. Removes the space-click conflict - music starts, and pauses again.",
  "icons": {
    "72": "icons/72.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://open.spotify.com/*"
      ],
      "js": [
        "lib/play.js"
      ]
    }
  ]
}