Examine source code of Telegraph+

{
  "manifest_version": 2,
  "name": "Telegraph+",
  "version": "0.8",
  "description": "Some nice features for Telegra.ph",
  "browser_specific_settings": {
    "gecko": {
      "id": "alittlemore@telegra.ph"
    }
  },
  "icons": {
    "32": "icon.ico"
  },
  "content_scripts": [
    {
      "matches": [
        "*://telegra.ph/*"
      ],
      "css": [
        "tlph.css"
      ],
      "js": [
        "insert.js"
      ]
    }
  ]
}