Examine source code of Black Red X2

{
  "name": "Black Red X2",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Screenshot_2020-08-04 Generar tema Centro de Desarrolladores Complementos para Firefox.png"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(148, 28, 28, 1)",
      "toolbar": "rgba(33, 33, 33, 1)",
      "bookmark_text": "rgba(148, 28, 28, 1)",
      "toolbar_field": "rgba(163, 127, 127, 1)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)"
    }
  }
}