Examine source code of Substitutions

{
  "manifest_version": 2,
  "name": "Substitutions",
  "version": "2.1resigned1",
  "description": "Replaces some words, phrases, and pictures with more amusing ones.",
  "icons": {
    "48": "icons/subs-48.png",
    "96": "icons/subs-96.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "substitutions.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d3386ccc-e265-42a6-8d6d-048e27851aa0}"
    }
  }
}