Examine source code of Empty Cache Button

{
  "manifest_version": 2,
  "name": "Empty Cache Button",
  "description": "Cache clearing made easy. One click.",
  "version": "3.5resigned1",
  "author": "mvm",
  "icons": {
    "16": "icons/16.png",
    "19": "icons/19.png",
    "32": "icons/32.png",
    "38": "icons/38.png",
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "browser_action": {
    "default_title": "Empty Cache",
    "default_icon": {
      "16": "icons/16.png",
      "19": "icons/19.png",
      "32": "icons/32.png",
      "38": "icons/38.png",
      "48": "icons/48.png",
      "96": "icons/96.png"
    }
  },
  "options_ui": {
    "page": "options/index.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "F9"
      }
    }
  },
  "permissions": [
    "notifications",
    "browsingData",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4cc4a13b-94a6-7568-370d-5f9de54a9c7f}"
    }
  }
}