Examine source code of Alu_Grey

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#a8a8a8",
      "tab_background_text": "#2b2a2a"
    }
  },
  "version": "2.0",
  "name": "Alu_Grey",
  "manifest_version": 2,
  "description": "A very simple brushed aluminum/grayish gradient. "
}