Examine source code of User Script Loader

{
  "manifest_version": 2,
  "name": "User Script Loader",
  "version": "1.0.0",
  "description": "A minimal extension to store and inject custom JavaScript (user scripts) into specified pages.",
  "permissions": [
    "storage",
    "<all_urls>",
    "tabs"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "user-script-loader@example.com"
    }
  }
}