Examine source code of Kotranium

{
  "name": "Kotranium DARK",
  "manifest_version": 2,
  "version": "5.0",
  "theme": {
    "images": {
      "theme_frame": "Unbenannt-1.png"
    },
    "colors": {
      "frame": "rgba(23, 23, 23, 1)",
      "tab_background_text": "rgba(155, 212, 158, 0.51)",
      "toolbar": "rgba(110, 110, 110, 0.41)",
      "bookmark_text": "rgba(63, 209, 34, 0.91)",
      "toolbar_field": "rgba(148, 148, 148, 0.36)",
      "toolbar_field_text": "rgba(252, 239, 251, 0.91)"
    }
  }
}