Examine source code of Song Vocal Extractor

{
  "manifest_version": 2,
  "name": "Song Vocal Extractor",
  "description": "Extract Vocals from music or sound files.",
  "version": "1.0.0",
  "permissions": [
    "background"
  ],
  "background": {
    "page": "bg.html",
    "persistent": true
  },
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_action": {
    "popup": "popup.html",
    "default_popup": "default.html"
  }
}