Examine source code of Bluer Dark Mode

{
  "name": "Dark Mode Bluer",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Dark Mode Bluer.png"
    },
    "colors": {
      "frame": "rgba(0, 0, 33, 1)",
      "tab_background_text": "rgba(182, 182, 186, 1)",
      "toolbar": "rgba(0, 0, 77, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 0, 51, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(0, 0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{23a4c377-8821-47e9-b0ad-605433a6a89a}"
    }
  }
}