Examine source code of TwitterCleanify

{
  "manifest_version": 2,
  "name": "TwitterCleanify",
  "version": "1.6resigned1",
  "description": "Limit twitter posts per one post per author daily - EXPERIMENTAL.",
  "icons": {
    "48": "icons/twitterify-48.png",
    "128": "icons/twitterify-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/"
      ],
      "js": [
        "twitterify.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{92d820ef-2664-4651-a4fc-11956013967d}"
    }
  }
}