Examine source code of Steam Browser Theme

{
  "name": "SteamBrowser",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "0.png"
    },
    "colors": {
      "frame": "rgba(42, 46, 51, 0)",
      "tab_background_text": "rgba(91, 100, 110, 1)",
      "toolbar": "rgba(42, 46, 51, 1)",
      "bookmark_text": "rgba(116, 122, 128, 1)",
      "toolbar_field": "rgba(47, 53, 64, 1)",
      "toolbar_field_text": "rgba(126, 166, 75, 1)",
      "tab_line": "rgba(31, 68, 90, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0130518e-04f3-4532-ad2a-308def06930a}"
    }
  }
}