Examine source code of Old Metal Sheet

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#030303"
    }
  },
  "version": "2.0",
  "name": "Old Metal Sheet",
  "manifest_version": 2,
  "description": "Am image of an old metal sheet that looks minimal but suits a great many themes, operating systems and wallapers."
}