Examine source code of Blue/White

{
  "name": "Blue/White",
  "manifest_version": 2,
  "version": "1.1resigned1",
  "theme": {
    "images": {
      "theme_frame": "Anmerkung 2019-04-01 115858.jpg"
    },
    "colors": {
      "frame": "rgba(44, 20, 235, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(255, 255, 255, 1)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(255, 255, 255, 1)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8675ab6a-090c-4b47-827d-7079fb6aa798}"
    }
  }
}