Examine source code of sandstone66

{
  "theme": {
    "images": {
      "theme_frame": "sandstone66-head.jpg"
    },
    "colors": {
      "frame": "#3d0a0a",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "sandstone66",
  "manifest_version": 2,
  "description": "a natural-looking texture that won't swamp text"
}