Examine source code of Dark mushroom

{
  "name": "Dark mushroom",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Mushroom laptop - Copie (2).jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(0, 0, 0, 0.52)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(69, 4, 2, 0.84)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(56, 1, 1, 0.22)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ce97c300-9d52-43df-b655-2f2ebeeed8c9}"
    }
  }
}