Examine source code of Steam Engine for Firefox

{
  "name": "Steam Engine for Firefox",
  "manifest_version": 2,
  "version": "5.0",
  "theme": {
    "images": {
      "theme_frame": "SteamEngineH.jpg"
    },
    "colors": {
      "frame": "rgba(46, 57, 89, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(45, 56, 89, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(45, 56, 89, 0.03)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  }
}