Examine source code of Relax Theme For Developer

{
  "name": "Relax Theme For Developer",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "background for firefox.jpg"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(103, 130, 235, 1)",
      "toolbar": "rgba(36, 55, 122, 1)",
      "bookmark_text": "rgba(11, 25, 79, 1)",
      "toolbar_field": "rgba(83, 99, 163, 1)",
      "toolbar_field_text": "rgba(170, 183, 235, 1)",
      "tab_line": "rgba(158, 174, 240, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f451a10b-07ee-4488-b265-aab2a36c6cfd}"
    }
  }
}