Examine source code of Problem To Pickle

{
  "manifest_version": 2,
  "name": "Problem To Pickle",
  "version": "1.0",
  "description": "Replaces the word 'problem' with word 'pickle' every where in the text on web page for each web site.",
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_end"
    }
  ],
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_action": {
    "default_icon": "images/icon32.png"
  }
}