Examine source code of Blue Grey Minimal Simple

{
  "name": "Blue Grey Minimal Simple",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Screenshot 2023-03-13 150255.png"
    },
    "colors": {
      "frame": "rgba(133, 140, 158, 1)",
      "tab_background_text": "rgba(60, 64, 77, 1)",
      "toolbar": "rgba(116, 122, 140, 1)",
      "bookmark_text": "rgba(60, 64, 77, 1)",
      "toolbar_field": "rgba(102, 107, 122, 1)",
      "toolbar_field_text": "rgba(60, 64, 77, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d5f753f1-1698-4166-882c-fd8f151fc77d}"
    }
  }
}