Examine source code of Caphona

{
  "name": "Caphona",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "skull.svg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(233, 240, 17, 1)",
      "bookmark_text": "rgba(250, 23, 15, 1)",
      "toolbar_field": "rgba(184, 46, 230, 1)",
      "toolbar_field_text": "rgba(4, 245, 0, 1)",
      "tab_line": "rgba(247, 15, 15, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0ad1bb64-2d00-42c2-9bf8-f9d8aa3ded64}"
    }
  }
}