Examine source code of Smooth Slate

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#2e2e44",
      "tab_background_text": "#bebec3"
    }
  },
  "version": "2.0",
  "name": "Smooth Slate",
  "manifest_version": 2,
  "description": "Shaded slate-blue fill with vertical accent lines"
}