Examine source code of GRadient Blue.Lite

{
  "theme": {
    "images": {
      "theme_frame": "header.jpg"
    },
    "colors": {
      "frame": "#e64a0c",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "GRadient Blue.Lite",
  "manifest_version": 2,
  "description": "My first theme. This shows a gradient (blue)."
}