Examine source code of Octotree Theme

{
  "description": "A Browser Extension which gives different filetypes different icons, and code color theme to GitHub and Octotree for free.",
  "version": "1.4.3",
  "author": "Thanh Vu",
  "homepage_url": "https://octotree-theme.web.app/",
  "manifest_version": 2,
  "name": "Octotree Theme",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*",
        "https://gist.github.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icons/icon16.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_icon": "icons/icon64-disabled.png",
    "default_popup": "popup-disabled.html"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "web_accessible_resources": [
    "*.woff2",
    "assets/**/*"
  ],
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ],
  "optional_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "octotree-theme-icon@misa198.com"
    }
  }
}