Examine source code of Dark red matte

{
  "name": "Dark red matte",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Screen_Shot_2020_06_02_at_9.53.58_AM.jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 0)",
      "tab_background_text": "rgba(199, 0, 0, 0.6)",
      "toolbar": "rgba(20, 20, 20, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 0, 0, 1)",
      "toolbar_field_text": "rgba(191, 191, 191, 1)",
      "tab_line": "rgba(0, 0, 0, 0)"
    }
  }
}