Examine source code of Shrekify

{
  "description": "Adds more Shrek in your life. Randomly replaces a single image on 1% of pages with an image of Shrek.",
  "manifest_version": 2,
  "name": "Shrekify",
  "version": "1.1resigned1",
  "applications": {
    "gecko": {
      "id": "shrekify@code-moon.com"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "libs/jquery-3.0.0.min.js",
        "src/shrekify.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "48": "src/images/icon48.png"
  },
  "web_accessible_resources": [
    "src/images/1/shrek1.png",
    "src/images/1/shrek2.png",
    "src/images/1/shrek3.png",
    "src/images/1/shrek4.png",
    "src/images/1/shrek5.png",
    "src/images/1/shrek6.png",
    "src/images/1/shrek7.png",
    "src/images/1/shrek8.png",
    "src/images/1/shrek9.png",
    "src/images/1/shrek10.png",
    "src/images/1.3/shrek1.png",
    "src/images/1.3/shrek2.png",
    "src/images/1.3/shrek3.png",
    "src/images/1.3/shrek4.png",
    "src/images/1.3/shrek5.png",
    "src/images/1.3/shrek6.png",
    "src/images/1.3/shrek7.png",
    "src/images/1.3/shrek8.png",
    "src/images/1.3/shrek9.png",
    "src/images/1.3/shrek10.png",
    "src/images/1.5/shrek1.png",
    "src/images/1.5/shrek2.png",
    "src/images/1.5/shrek3.png",
    "src/images/1.5/shrek4.png",
    "src/images/1.5/shrek5.png",
    "src/images/1.5/shrek6.png",
    "src/images/1.5/shrek7.png",
    "src/images/1.5/shrek8.png",
    "src/images/1.5/shrek9.png",
    "src/images/1.5/shrek10.png",
    "src/images/1.7/shrek1.png",
    "src/images/1.7/shrek2.png",
    "src/images/1.7/shrek3.png",
    "src/images/1.7/shrek4.png",
    "src/images/1.7/shrek5.png",
    "src/images/1.7/shrek6.png",
    "src/images/1.7/shrek7.png",
    "src/images/1.7/shrek8.png",
    "src/images/1.7/shrek9.png",
    "src/images/1.7/shrek10.png",
    "src/images/1.9/shrek1.png",
    "src/images/1.9/shrek2.png",
    "src/images/1.9/shrek3.png",
    "src/images/1.9/shrek4.png",
    "src/images/1.9/shrek5.png",
    "src/images/1.9/shrek6.png",
    "src/images/1.9/shrek7.png",
    "src/images/1.9/shrek8.png",
    "src/images/1.9/shrek9.png",
    "src/images/1.9/shrek10.png"
  ]
}