Examine source code of ScreenshotMonitor

{
  "manifest_version": 2,
  "name": "ScreenshotMonitor",
  "version": "2.2",
  "author": "Rodion Nikolaev",
  "homepage_url": "https://screenshotmonitor.com",
  "description": "Browser extension for ScreenshotMonitor.com service",
  "icons": {
    "48": "images/icon.png",
    "96": "images/icon.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "48": "images/icon.png",
      "96": "images/icon.png",
      "128": "images/icon.png"
    },
    "default_title": "ScreenshotMonitor",
    "default_popup": "extension.html"
  },
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "*://screenshotmonitor.com/*",
    "cookies",
    "storage",
    "webRequest"
  ]
}