Examine source code of OnlyDarkPurple

{
  "name": "OnlyDarkPurple",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "backgr.png"
    },
    "colors": {
      "frame": "rgba(102, 17, 109, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(136, 23, 152, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(102, 17, 109, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{02bb4f8a-7f9d-4c90-9634-3a280a63943c}"
    }
  }
}