Examine source code of Sleek black

{
  "theme": {
    "images": {
      "theme_frame": "Untitled-1.png"
    },
    "colors": {
      "frame": "#e6e1e1",
      "tab_background_text": "#757575"
    }
  },
  "version": "2.0",
  "name": "Sleek black",
  "manifest_version": 2,
  "description": "A sleek persona for your Firefox..."
}