Examine source code of set icon path plus

{
  "name": "set icon path plus",
  "description": "Click browser action icon to change color! A browser action which changes its icon when clicked",
  "version": "1.3",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "name": "Click to change the icon's color"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{4c8a74b7-a4c4-45b4-a4cb-6b52c54e1608}"
    }
  }
}