Examine source code of Proxy Manager

{
  "manifest_version": 2,
  "name": "Proxy Manager",
  "version": "1.2",
  "description": "A browser extension for managing multiple proxies",
  "background": {
    "scripts": [
      "scripts/common.js",
      "scripts/background.js"
    ]
  },
  "permissions": [
    "proxy",
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "96": "icons/icon96.png"
    },
    "default_title": "Proxy manager",
    "default_popup": "pages/popup.html",
    "browser_style": true
  },
  "options_ui": {
    "page": "pages/options.html",
    "browser_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "proxymanager@rend.al",
      "strict_min_version": "91.1.0"
    }
  }
}