Examine source code of Fartify

{
  "manifest_version": 2,
  "name": "Fartify",
  "short_name": "Fartify",
  "version": "1.3resigned1",
  "description": "Changes apologies to farts in Slack. Replaces variations of sorry/apology in messages",
  "author": "David Sullins",
  "icons": {
    "48": "icons/fart-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.slack.com/*"
      ],
      "js": [
        "fartify.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f6e97ecf-2562-400a-8daf-b42dd307975d}"
    }
  }
}