Examine source code of MM3 Proxy Switch

{
  "manifest_version": 2,
  "name": "MM3-ProxySwitch",
  "short_name": "ProxySwitch",
  "description": "__MSG_appDescription__",
  "version": "2019",
  "author": "MM3Tools",
  "icons": {
    "48": "img/MM3_48.svg",
    "96": "img/MM3_96.svg"
  },
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "ProxySwitch@MM3Tools.com",
      "strict_min_version": "60.0"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_popup": "popup.html",
    "default_icon": {
      "16": "img/MM3_16off.svg",
      "32": "img/MM3_32off.svg"
    }
  },
  "background": {
    "scripts": [
      "util.js",
      "ProxySwitch.js"
    ]
  },
  "permissions": [
    "storage",
    "proxy",
    "browsingData",
    "http://*/*",
    "https://*/*"
  ],
  "commands": {
    "ProxySwitch-1": {
      "suggested_key": {
        "default": "Ctrl+Shift+1"
      },
      "description": "1. __MSG_ProxyConfiguration__"
    },
    "ProxySwitch-2": {
      "suggested_key": {
        "default": "Ctrl+Shift+2"
      },
      "description": "2. __MSG_ProxyConfiguration__"
    },
    "ProxySwitch-3": {
      "suggested_key": {
        "default": "Ctrl+Shift+3"
      },
      "description": "3. __MSG_ProxyConfiguration__"
    },
    "ProxySwitch-4": {
      "suggested_key": {
        "default": "Ctrl+Shift+4"
      },
      "description": "4. __MSG_ProxyConfiguration__"
    }
  },
  "options_ui": {
    "browser_style": true,
    "open_in_tab": true,
    "page": "setting.html"
  }
}