Examine source code of GitHub Save

{
  "manifest_version": 2,
  "name": "GitHub Save",
  "version": "1.1.0",
  "permissions": [
    "identity",
    "cookies",
    "https://api.githubsave.samuelyyy.com/*",
    "tabs"
  ],
  "description": "If you ever wanted to save inidividual files from a GitHub repository that piqued your interest, this extension is for you.",
  "icons": {
    "16": "icons/githubsave16.png",
    "48": "icons/githubsave48.png",
    "128": "icons/githubsave128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.github.com/*"
      ],
      "js": [
        "index.js"
      ],
      "css": [
        "./main.css"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "injectable.js"
  ],
  "browser_action": {
    "default_icon": "icons/githubsave48.png",
    "default_title": "GitHub Save",
    "default_popup": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "githubsave@example.com"
    }
  }
}