Examine source code of Simple flat gray tones

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Simple flat gray tones",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(210, 215, 219)",
      "toolbar_text": "rgb(59, 59, 59)",
      "frame": "rgb(86, 93, 97)",
      "tab_background_text": "rgb(201, 206, 209)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(59, 59, 59)",
      "tab_line": "rgb(86, 93, 97)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(59, 59, 59)",
      "tab_loading": "rgb(86, 93, 97)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8d767ba4-e1d9-4d8a-9413-2430592b7f0e}"
    }
  }
}