Examine source code of Clear Cache & Refresh

{
  "manifest_version": 2,
  "name": "Clear Cache & Refresh",
  "version": "1.0",
  "description": "Quickly clear cache and refresh the current tab with one click.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "browsingData",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Clear Cache & Refresh",
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "clear-cache-refresh@hqaddon"
    }
  }
}