Examine source code of CSS Toggler

{
  "manifest_version": 2,
  "name": "CSS Toggler",
  "version": "1.2",
  "description": "Browser extension to quickly toggle CSS.",
  "icons": {
    "48": "assets/css-enabled-48.png",
    "96": "assets/css-enabled-96.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "assets/css-enabled-48.png",
      "96": "assets/css-enabled-96.png"
    },
    "default_title": "Click to disable CSS"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/toggle-css.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{16898b73-edd0-419f-a0a9-e5afd2a4c904}"
    }
  }
}