Examine source code of AudioSketch

{
  "manifest_version": 2,
  "name": "AudioSketch",
  "version": "1.0",
  "description": "Real-time waveform visualizer in popup using AnalyserNode and Canvas. Load a local audio file or play audio and watch waveform.",
  "browser_action": {
    "default_title": "AudioSketch",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e38320bd-4441-4847-8161-288a1db0d1db}"
    }
  }
}