Examine source code of hero test theme

{
  "name": "test_theme",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "firefoxtheme.png"
    },
    "colors": {
      "frame": "rgba(80, 150, 90, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(30, 28, 41, 0.44)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1598a0a5-10b7-4570-8a6d-303efd4d75ac}"
    }
  }
}