Examine source code of Circuits_grey_type

{
  "theme": {
    "images": {
      "theme_frame": "circuits_1_top.png"
    },
    "colors": {
      "frame": "#c7c3c3",
      "tab_background_text": "#c7c3c3"
    }
  },
  "version": "2.0",
  "name": "Circuits_grey_type",
  "manifest_version": 2
}