Examine source code of Contrast Slider

{
  "manifest_version": 2,
  "name": "Contrast Control",
  "version": "3.1",
  "description": "Adjust contrast and color assist",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png",
    "96": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7c7038b0-6f45-4a8f-bc05-8aed4598765e}"
    }
  }
}