Examine source code of Emoji Band

{
  "manifest_version": 2,
  "name": "Emoji Band",
  "version": "1.0",
  "description": "Detects typed emoji in input fields and plays a matching instrument sound (e.g., 🎸 = guitar, 🥁 = drums, 🎹 = piano).",
  "icons": {},
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "emoji-band.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8fa61f1b-2f5b-42f0-9321-44daeffa86bb}"
    }
  }
}