Examine source code of Minimalist Grey

{
  "name": "Minimalist Grey",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Theme Background.png"
    },
    "colors": {
      "frame": "rgba(221, 223, 226, 1)",
      "tab_background_text": "rgba(8, 8, 8, 1)",
      "toolbar": "rgba(221, 223, 226, 1)",
      "bookmark_text": "rgba(8, 8, 8, 1)",
      "toolbar_field": "rgba(221, 223, 226, 1)",
      "toolbar_field_text": "rgba(8, 8, 8, 1)",
      "tab_line": "rgba(221, 223, 226, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d9c27f6d-6526-4095-8c61-76ca832f73ac}"
    }
  }
}