Reticle

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Reticle",
  "version": "1.0.1",
  "manifest_version": 2,
  "description": "Drag and resize a ruler overlay to quickly measure pixel dimensions, positioning, and alignment of elements on any webpage.",
  "options_page": "settings.html",
  "icons": {
    "16": "images/icon-16.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "19": "images/browser-action-19.png",
      "38": "images/browser-action-38.png"
    },
    "default_title": "Enable Reticle"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+X",
        "windows": "Ctrl+Shift+X",
        "mac": "Command+Shift+X",
        "chromeos": "Ctrl+Shift+X",
        "linux": "Ctrl+Shift+X"
      }
    }
  }
}