Examine source code of Userchrome Toggle

{
  "manifest_version": 2,
  "name": "Userchrome Toggle",
  "version": "1.2",
  "description": "This extension allows you to toggle userchrome.css styles on-the-fly with buttons and hotkeys.",
  "icons": {
    "48": "images/icon.svg"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "userchrome-toggle@joolee.nl"
    }
  },
  "browser_action": {
    "default_title": "Toggle userchrome style",
    "default_icon": "images/toggle-off.svg",
    "default_area": "navbar",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "uct-background.js"
    ]
  },
  "commands": {
    "toggle-style-1": {
      "suggested_key": {
        "default": "Ctrl+Shift+1"
      },
      "description": "Toggle userchrome style 1"
    },
    "toggle-style-2": {
      "suggested_key": {
        "default": "Ctrl+Shift+2"
      },
      "description": "Toggle userchrome style 2"
    },
    "toggle-style-3": {
      "suggested_key": {
        "default": "Ctrl+Shift+3"
      },
      "description": "Toggle userchrome style 3"
    }
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true,
    "chrome_style": true
  },
  "permissions": [
    "notifications",
    "storage"
  ]
}