Examine source code of Catkins

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#878585",
      "tab_background_text": "#f7c308"
    }
  },
  "version": "2.0",
  "name": "Catkins",
  "manifest_version": 2,
  "description": "Catkins or pussy willow blooms in the early spring."
}