Examine source code of Dead Rat Replacer

{
  "name": "Dead Rat Replacer",
  "version": "2.0",
  "description": "Replace every image by a dead rat diploma",
  "web_accessible_resources": [
    "images/*.jpg"
  ],
  "browser_action": {
    "icons": {
      "16": "images/rat_emoji.png",
      "48": "images/rat_emoji.png",
      "128": "images/rat_emoji.png"
    },
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "manifest_version": 2
}