Examine source code of Patch it!

{
  "manifest_version": 2,
  "name": "Patch it!",
  "version": "0.1.0",
  "description": "A JavaScript/CSS loader for Firefox",
  "homepage_url": "https://github.com/TheOtterlord/patch-it",
  "icons": {
    "64": "assets/icon-64.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_title": "Patch it!",
    "default_icon": "assets/icon-64.png",
    "default_popup": "src/popup/index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "src/index.js"
      ]
    }
  ]
}