Examine source code of Classic Castlevania

{
  "name": "Classic Castlevania",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "castlevaniapersona.jpg"
    },
    "colors": {
      "frame": "#0a0202",
      "tab_background_text": "#fae900",
      "toolbar": "rgba(23, 21, 21, 0.39)",
      "bookmark_text": "rgba(255, 66, 66, 1)",
      "toolbar_field": "rgba(0, 0, 0, 0.55)",
      "toolbar_field_text": "rgba(232, 211, 211, 1)"
    }
  }
}