Examine source code of Load Progress Bar

{
  "manifest_version": 2,
  "name": "Load Progress Bar",
  "version": "0.25",
  "description": "Adds minimalistic load progress bar on each page",
  "homepage_url": "https://github.com/luben/load-progress-bar",
  "applications": {
    "gecko": {
      "id": "load-progress-bar@luben.github.com",
      "strict_min_version": "58.0"
    }
  },
  "icons": {
    "48": "icons/load_progress_bar-48.png",
    "96": "icons/load_progress_bar-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "js/load_progress_bar.js"
      ],
      "run_at": "document_start"
    }
  ],
  "options_ui": {
    "page": "settings/options.html"
  },
  "permissions": [
    "storage"
  ]
}