Examine source code of Hack

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#404040",
      "tab_background_text": "#00ff66"
    }
  },
  "version": "2.0",
  "name": "Hack",
  "manifest_version": 2,
  "description": "This theme was created for a nicer look to the Kali Linux's 2.0 Ice Weasel."
}