Examine source code of the sign

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#bcdff7",
      "tab_background_text": "#e3fffd"
    }
  },
  "version": "2.0",
  "name": "the sign",
  "manifest_version": 2,
  "description": "pictures of \"the tree\" made by Kouw-Art in the forest of Amsterdam."
}