Examine source code of Concept21

{
  "theme": {
    "images": {
      "theme_frame": "Concept21_Header_Vintagedaddyo.jpg"
    },
    "colors": {
      "frame": "#c9c9c9",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Concept21",
  "manifest_version": 2,
  "description": "Simple lines combo for smooth abstract approach"
}