Examine source code of Missingno

{
  "name": "Missingno",
  "version": "0.0.7resigned1",
  "author": "Henry Smith",
  "manifest_version": 2,
  "description": "Show the descriptions people put on the images they post on Twitter",
  "homepage_url": "https://github.com/hnrysmth/missingno",
  "permissions": [
    "http://twitter.com/*"
  ],
  "icons": {
    "16": "logo16.png",
    "48": "logo48.png",
    "128": "logo128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*"
      ],
      "css": [
        "missingno.css"
      ],
      "js": [
        "missingno.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{0ad42635-5e3d-4914-94b6-42a30cf53e6f}"
    }
  }
}