Examine source code of Vegvisir.is

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Vegvisir.is",
  "manifest_version": 2,
  "description": "I am a fan of minimalist designs. And I like Iceland. I also like history. So I made this superlightweight theme that has a Vegvisir as its sole graphical element and coats the rest in a snowy white."
}