Examine source code of ThinkPad Dark

{
  "name": "ThinkPad Dark",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "gray.png"
    },
    "colors": {
      "frame": "rgba(16, 16, 16, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(16, 16, 16, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(16, 16, 16, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(227, 39, 38, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6e5fb55f-70fa-4570-8e28-aabc3b38aa8e}"
    }
  }
}