Examine source code of Victorian pattern

{
  "theme": {
    "images": {
      "theme_frame": "Untitled.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Victorian pattern",
  "manifest_version": 2,
  "description": "It actually looks much more subtle than in the preview ;) Made with a pattern from <a href=\"https://outgoing.prod.mozaws.net/v1/0813092959e24caaafda2d7fcb7c6ce132395006f4cb5365363585428ba5dcf1/http%3A//www.arsgrafik.com/\" rel=\"nofollow\">http://www.arsgrafik.com/</a>"
}