Examine source code of MB Grey

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "MB Grey",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(255, 255, 255)",
      "toolbar_text": "rgb(71, 71, 71)",
      "frame": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(46, 46, 46)",
      "toolbar_field": "rgb(147, 147, 147)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(41, 41, 41)",
      "icons": "rgb(0, 0, 0)",
      "tab_selected": "rgb(146, 146, 146)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(255, 255, 255)",
      "toolbar_field_border": "rgb(255, 255, 255)",
      "toolbar_top_separator": "rgb(255, 255, 255)",
      "toolbar_vertical_separator": "rgb(255, 255, 255)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3382b7e5-0ce5-4af2-8f51-62b46f721c9b}"
    }
  }
}