Examine source code of charcoal-black

{
  "name": "charcoal-black",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "Screenshot_2022-04-14_20-11-46.png"
    },
    "colors": {
      "frame": "rgba(53, 53, 53, 1)",
      "tab_background_text": "rgba(212, 212, 212, 1)",
      "toolbar": "rgba(53, 53, 53, 1)",
      "toolbar_field": "rgba(66, 66, 66, 1)",
      "toolbar_field_text": "rgba(196, 196, 196, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{58fcbac7-d7f7-4e63-96d3-e1116c0c97c8}"
    }
  }
}