chrome/test/data/extensions/api_test/file_system/save_background/manifest.json

{
  "name": "chrome.fileSystem save from background.",
  "version": "0.1",
  "description": "Test for chrome.fileSystem.chooseFile save from background.",
  "app": {
    "background": {
      "scripts": ["background.js"]
    }
  },
  "permissions": [
    {
      "fileSystem": ["write"]
    }
  ]
}