Examine source code of Steelbourne

{
  "manifest_version": 2,
  "name": "Steelbourne",
  "version": "1.0",
  "description": "A dark steel blue and prussian browser theme.",
  "browser_specific_settings": {
    "gecko": {
      "id": "steelbourne@mytheme",
      "strict_min_version": "68.0"
    }
  },
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#0a1220",
      "frame_inactive": "#0e1828",
      "tab_background_text": "#5878a0",
      "tab_selected": "#142038",
      "tab_line": "#3870c0",
      "tab_loading": "#3870c0",
      "tab_text": "#c0d8f0",
      "toolbar": "#101c30",
      "toolbar_text": "#b0cce8",
      "toolbar_field": "#162438",
      "toolbar_field_text": "#c8dff0",
      "toolbar_field_border": "#223450",
      "toolbar_field_focus": "#1c2e48",
      "toolbar_field_text_focus": "#e0f0ff",
      "toolbar_field_border_focus": "#3870c0",
      "toolbar_top_separator": "#060c16",
      "toolbar_bottom_separator": "#060c16",
      "toolbar_vertical_separator": "#162438",
      "icons": "#3068b8",
      "icons_attention": "#4888d8",
      "button_background_hover": "#1a2e48",
      "button_background_active": "#223450",
      "popup": "#101c30",
      "popup_text": "#b0cce8",
      "popup_border": "#223450",
      "popup_highlight": "#1c2e48",
      "popup_highlight_text": "#e0f0ff",
      "sidebar": "#0a1220",
      "sidebar_text": "#6888b0",
      "sidebar_highlight": "#1c2e48",
      "sidebar_highlight_text": "#e0f0ff",
      "sidebar_border": "#162438",
      "ntp_background": "#0a1220",
      "ntp_text": "#b0cce8"
    }
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  }
}