Examine source code of Juno's Theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Juno's Theme",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(51, 51, 51)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(241, 150, 31)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_hover": "rgb(241, 150, 31)",
      "icons_attention": "rgb(241, 150, 31)",
      "icons": "rgb(255, 255, 255)",
      "ntp_background": "rgb(0, 0, 0)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(255, 255, 255)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "sidebar_border": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(241, 150, 31)",
      "sidebar_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(241, 150, 31)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{84bf7a6f-7c08-457c-a29a-e452c628aa0d}"
    }
  }
}