Examine source code of BlackPink:3

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "BlackPink:3",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(255, 0, 86)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 0, 86)",
      "toolbar_field": "rgba(255, 0, 86, 0.21)",
      "toolbar_field_text": "rgb(255, 0, 86)",
      "tab_line": "rgb(255, 0, 86)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(255, 0, 86)",
      "tab_loading": "rgb(255, 0, 86)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a2647c93-57b6-4c39-b0e3-c661f152ff61}"
    }
  }
}