Examine source code of cantaloupe detector

{
  "manifest_version": 2,
  "name": "cantaloupe",
  "version": "1.0",
  "description": "plays invincible by deaf kev for each 'cantaloupe' found on any page open",
  "permissions": [
    "activeTab",
    "<all_urls>"
  ],
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "shuv@maybe.yuh"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    "audio.mp3"
  ]
}