Examine source code of Tab Sound Mapper

{
  "manifest_version": 2,
  "name": "Tab Sound Mapper",
  "version": "1.0",
  "description": "Display a visual map of tabs playing audio.",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icons/icon48.png",
    "default_popup": "popup.html",
    "default_title": "Tab Sound Mapper"
  },
  "icons": {
    "48": "icons/icon48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d3c6bcb2-5a21-418c-9386-78325b8df6f0}"
    }
  }
}