Examine source code of GitHub Repo Size

{
  "manifest_version": 2,
  "name": "GitHub Repo Size",
  "description": "View GitHub repository sizes directly on repo pages.",
  "version": "0.1.0",
  "permissions": [
    "activeTab",
    "tabs",
    "https://api.github.com/*",
    "https://github.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{ea719b09-1d5f-44a9-80ad-8b209452ff4a}"
    }
  },
  "browser_action": {
    "default_title": "GitHub Repo Size",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*/*"
      ],
      "run_at": "document_idle",
      "css": [
        "content-scripts/content.css"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}