Examine source code of Red 'n' Black

{
  "name": "Red 'n' Black",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Untitled233_20211117125130.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 0)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(3, 3, 3, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(138, 40, 40, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{21afde8b-0ed2-49ab-9e76-2f1c8c96b0f1}"
    }
  }
}