Examine source code of Music Enhancer

{
  "manifest_version": 2,
  "name": "Music Enhancer",
  "version": "3.5",
  "description": "Boost volume up to 300%, custom EQ, presets, 3D audio, and live visualizer on every website.",
  "icons": {
    "16": "imgs/16.png",
    "32": "imgs/32.png",
    "48": "imgs/48.png",
    "128": "imgs/128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "imgs/16.png",
      "32": "imgs/32.png",
      "48": "imgs/48.png",
      "128": "imgs/128.png"
    },
    "default_popup": "popup.html",
    "default_title": "Music Enhancer"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    "imgs/16.png",
    "imgs/32.png",
    "imgs/48.png",
    "imgs/128.png",
    "dancing.mp4"
  ],
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "music-enhancer@archimetrix",
      "strict_min_version": "91.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}