Examine source code of Dark Squares theme

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ff0000",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Dark Squares theme",
  "manifest_version": 2,
  "description": "Dark theme with a nice faded effect created with overlayed squares."
}