Examine source code of Fedora modern dark

{
  "manifest_version": 2,
  "name": "Fedora modern dark",
  "version": "1.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d25cc797-ed39-492a-a981-0d243052af89}"
    }
  },
  "theme": {
    "images": {
      "theme_frame": "fedora-workstation-logo-light.png"
    },
    "colors": {
      "frame": "#113280",
      "tab_background_text": "#2F8BEF",
      "toolbar": "#0B57A4",
      "toolbar_text": "#FFFFFF",
      "toolbar_field": "#00178C",
      "toolbar_field_text": "#FFFFFF",
      "tab_loading": "#2F8BEF"
    },
    "properties": {
      "color_scheme": "dark",
      "content_color_scheme": "dark"
    }
  }
}