Examine source code of GoogleArtProject 3

{
  "theme": {
    "images": {
      "theme_frame": "monkbytheseacaspardavidfriedrich.jpg"
    },
    "colors": {
      "frame": "#e5e8c1",
      "tab_background_text": "#f0f2d5"
    }
  },
  "version": "2.0",
  "name": "GoogleArtProject 3",
  "manifest_version": 2,
  "description": "Monk by the sea \nCaspar David Friedrich"
}