Examine source code of Feather

{
  "manifest_version": 2,
  "name": "Feather",
  "version": "3.1",
  "description": "Feather, fork of SweezeBreeze tailored for usage with TBH.",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.nationstates.net/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}